Editor's Note: Please see the PDF of this article posted above to see the tables and figures.
Patient education and counseling may be the key to proper allergen avoidance and remission of the dermatitis.
Allergic Contact Dermatitis (ACD) is an important disease that notably affects 14.5 million Americans each year.1 The economic impact of this disease is high in terms of both patient morbidity and loss of income, school and work, not to mention significant expenditures for visits to healthcare providers and for medicaments.1 Once patch testing is performed and a culprit has been identified, education becomes the critical intervention to ensure adherence to an avoidance regimen. With allergen avoidance, remission of the dermatitis often ensues. If the patient is unable to comply with the avoidance regimen, they are at risk for recurrent or sustained dermatitis or progression to a systematized presentation.2,3 In fact, education of the patient often begins before the diagnostic patch test is ever placed. This ensures that the patient has an appropriate understanding of potential outcomes and his or her central role in both the disease and treatment.
During the initial consultation, patients are often taught about the pathophysiology of ACD: its delayed presentation; its relationship with the immune system (sensitization to a chemical and then elicitation of a dermatitis with re-exposure); and its occurrence at any point in time, even to something the patient has been using regularly for a short period of time or even intermittently for years. In certain cases, the other key players, such as irritant contact dermatitis (ICD) and contact urticaria, may be explained via history (not patch testing) and can point to these as the correct diagnosis. It is important to note that ICD, the most prevalent form of contact dermatitis, can, at times, precede or be a concomitant diagnosis with ACD.4,5 Unlike ACD, ICD is not immune-mediated; it occurs secondary to contact with an irritating or abrasive substance. Contact urticaria (wheal and flare reaction), on the other hand, represents the least prevalent form of contact dermatitis. It is important to note that it is an immune-mediated phenomenon whose hallmark is an IgE and mast cell-mediated immediate-type hypersensitivity reaction. We acknowledge this form of hypersensitivity due to the severity of the potential deleterious anaphylactic-type reactions and direct the reader to key sources.6-8
In this section, we highlight ACD and explore top relevant allergens, regional and topic-based dermatitis presentations and clinical tips and pearls for diagnosis and treatment. This edition focuses on education of the patient.
Patient Counseling and Allergen Education in the Patch Test Clinic
Perhaps the most important aspect of the patch testing procedure is patient education, both pre and post patch test. If patients do not understand what they are being tested for, what they need to avoid and where they may encounter their allergen(s), it will be very difficult to ‘cure’ [remit] the contact dermatitis and have them remain clear.
It is essential to start with the basics. Many patients (and some referring physicians and clinical providers) think, erroneously, that patch testing is equivalent to scratch/intradermal testing and that it involves needle testing for items such as pollen, dust, mold and dander. However, patch testing is a reflection of T-cell mediated immunity (delayed type hypersensitivity; type IV immune reaction), which is a completely different test than scratch or intradermal testing. The latter is a reflection of an antibody-mediated, immediate hypersensitivity immune reaction (type I immune reaction) generally causing symptoms such as eye tearing, rhinorrhea and shortness of breath.
Types Of Allergens
The patch test allergens, in general, are found within personal care products used on the skin, hair and nails (preservatives, fragrances, surfactants or emulsifiers, for example) or are in items that come into contact with the skin: metals in jewelry, textile formaldehyde resins, rubber additives in gloves and clothing items, and so on. The cutaneous symptoms typically caused by contact allergens include rashes and sometimes skin swelling. Again, in general, direct contact of an allergen with the skin surface initiates the symptoms, although ingestion or inhalation of an allergen or parenteral exposure can occasionally cause a localized or generalized rash known as systemic contact dermatitis.9
Especially when dealing with occupational contact dermatitis, whether irritant or allergic, it is important for the diagnosing physician to have a plausible hypothesis for how putative allergens or irritants in the workplace would explain a patient’s distribution of dermatitis, whether it is direct contact with a substance (often with hand involvement), airborne exposure or splash exposure. For example, an administrative assistant working at a law office who blames her periumbilical eruption on her workplace and is nickel-allergic on patch testing would not be deemed to have occupational allergic contact dermatitis.
Essential Information Sheets
Many patients are overwhelmed by the names of some of the allergens tested, let alone synonyms and exposure sources – methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) has more syllables than supercalifragilistickexpialidocious. It is therefore helpful to have an educated assistant working with you in the office to review information sheets about allergens with your patients, answer any questions they may have and review product listings of suitable personal care products (PCPs) without their documented allergens. It is essential to have information sheets on tested allergens (paper or electronic copies) to give or e-mail to patients so they may review information at their leisure after the office visit.
Education Strategies
There can be a fair amount of denial, which can be a barrier to patients’ willingness to believe they may be allergic to a favorite cream or lotion. It is very important to patch test for these favorite items with the caveat that, sometimes, an allergen can be diluted when testing to a full product and can lead to a false negative. Certainly, if there’s a positive reaction, it makes a big impression. It is sometimes necessary to reinforce the notion that, since contact allergy is a reflection of delayed type hypersensitivity, a reaction can take place 24 to 48 hours after a product is applied to the skin (or worn, if it’s a textile), and is just not obvious to a patient. In one study, 50% of patients and physicians were unaware that a cosmetic contained a culprit allergen.10 Patients can also be reluctant to accept that they are allergic to products they’ve used for years without a problem. An explanation of the factors that contribute to elicitation of allergic contact dermatitis, including an impaired skin barrier, low environmental humidity and/or prolonged exposure time to an allergen, together with heat, pressure and friction, can help convince a skeptical patient.
It is also extremely convincing to take a photo of patients’ patch test reactions. After seeing an edematous plaque or bullous reaction, patients are more likely to believe they will need to avoid certain products. It is essential to have patients bring in their PCPs on the final patch test day. It is sometimes surprising, to the author, how many “nothings” patients are using on their skin. Circling or underlining documented allergens on a label is an effective education strategy. The author likes to reassure patients that they should not feel bad if almost everything they have been using is not suitable. Patients allergic to the top two cosmetic allergens, formaldehyde-releasing preservatives and fragrance,11 will often still be exposed to these allergens even after switching to numerous different PCPs prior to patch testing. It is vital to stress that they will be receiving a detailed list of products that are safe to use. Otherwise, patients can become overwhelmed and hopeless.
It may be worthwhile to group allergens into categories for your patient. For example, if a patient reacts to quaternium 15, fragrance or MCI/MI, these could be categorized as personal care product-type allergens. It is helpful to refrain from the word “cosmetic” when discussing these allergens with male patients, as some may be insulted if they are told they are allergic to a “cosmetic” allergen. For patients who react to formaldehyde, it is important to review the names of all the formaldehyde-releasing preservatives (FRPs). Patients need to be aware that they will almost never see the word “formaldehyde” on a shampoo or body wash label, but will often find FRPs in these products. Quaternium–15, 2-bromo-2-nitropropane-1,3-diol (bronopol), imidazolidinyl urea (imid urea), diazolidinyl urea and DMDM hydantoin are FRPs found in many shampoos, body washes and lotions. Patients who are formaldehyde-allergic should be familiar with these names. Some corticosteroids contain FRPs, including Ultravate and Halobetasol cream, which contain diazolidinyl urea. Cutivate cream contains imidazolidinyl urea, abbreviated as imid urea.
An excellent resource for exploring functions and synonyms for various multi-syllabic chemicals on a product label is the Council Link on the American Contact Dermatitis Society’s (ACDS) website (www.contactderm.org). This link gives a member physician access to information from the Personal Care Products Council and includes International Cosmetic Ingredient (INCI) names, trade names and functions and structures of chemicals.
The Marks, Elsner and Deleo textbook12 explicitly permits duplication of allergen information sheets for use in clinical practice. These information sheets can be copied, scanned and distributed. Additionally, the ACDS has information sheets available in PDF to members for patient education on their website within the Contact Allergen Management Program (CAMP) link under the Narratives List tab. For a yearly fee, www.preventice.com also offers the Contact Allergen Replacement Database (CARD), which generates lists of safe products patients may use. In addition, there is a free online service called www.mypatchlink.com that patients can be directed to watch videos about allergic contact dermatitis and specific allergens.
Textile Allergy Example
If one is testing only with the TRUE Test patch test, formaldehyde is a very good screening chemical for formaldehyde textile resin allergy; approximately 70% of those with a textile formaldehyde allergy will be detected.13 For a patient with a generalized eruption and formaldehyde allergy on patch testing, such a reaction could represent allergy to clothing formaldehyde resins. Formaldehyde textile resins can be present in permanent press/wrinkle-resistant fabrics, even if 100% cotton or blended fabrics (any natural fiber blended with a synthetic fiber). Suitable fabrics for such patients include 100% soft, wrinkly cotton, silk or linen, 100% polyester, nylon or acrylic.14 In a patient with a generalized eruption who reacts to formaldehyde on patch testing and is not using any PCPs containing FRPs, it is important to consider textile formaldehyde resins as potentially problematic.
P-phenylene diamine (PPD), the main hair dye sensitizer, and black rubber mix (BRM) can serve as screening allergens for textile dye allergy; in one study, PPD and BRM picked up approximately 50% of patients allergic to at least one ingredient of a textile dye mix.15 PPD and BRM reactions are therefore potentially clinically relevant allergens in a patient with generalized dermatitis suggesting a textile-type allergen — even in a patient who does not color his or her hair. It is up to the patch-testing physician to put the pieces of the puzzle together for patients and try to explain their patch test reactions in light of the their history, occupation and distribution of dermatitis.
Fragrance Allergy Example
Most patients are emphatic that they cannot be reacting to fragrance because they do not wear cologne or perfume. Many don’t realize that the causative fragrance allergen is usually present in a personal care product and not necessarily in a cologne or perfume.11 Additionally, many patients may be adamant that all their products are “fragrance free” or “hypoallergenic.” They are unaware that many products marketed as fragrance-free still contain fragrance chemicals (see Table 1). Due to a legal loophole, if a chemical is not used solely to impart an odor to the product, a fragrance chemical can be used in a “fragrance-free” product.16 Rose, lavender, coriander and cardamom are all present in various popular personal care products labeled fragrance-free.17 As such, a consumer with contact allergy really needs to pay special attention to all inactive ingredients in a product and not rely on marketing on the label. Additionally, many patients feel that “all natural” products are beneficial; however, in ancient times, fragrances were made from herbs, roots, flowers, woods and spices,18 and, therefore, patients allergic to fragrance may react to “all natural” products they are using.
Screening allergens for fragrance allergy present on the TRUE Test include fragrance mix I and balsam of Peru. Balsam of Peru (Myroxylon pereirae) is a very complex fragrance resin obtained from wounding a type of tree. Myroxylon pereirae contains more than 200 individual ingredients, including cinnamic acid, cinnamic alcohol, cinnamic aldehyde, benzyl alcohol, benzaldehyde, benzoic acid, isoeugenol, coniferyl alcohol and vanillin, among others.19
Rubber Additive Example
For patients reacting to rubber additives (thiuram mix, black rubber mix, carba mix, mercapto mix), counseling physicians should stress that these MAY be relevant for waistband dermatitis, bra dermatitis (ie, to elastic or foam portions of bras), hand dermatitis (in those wearing rubber gloves) and foot dermatitis (ie, from rubber additives in spongy/foamy portions of shoes and/or adhesives). It is important to note that sometimes patients will only be symptomatic in one location of the body and not every area of exposure. For example, some patients with rubber additive allergens will only have foot dermatitis but not waistband dermatitis, some may have hand dermatitis but not waistband or foot dermatitis and so forth. Pressure, friction, heat and humidity and exposure to irritants, all play a role in the manifestation of allergic contact dermatitis.
Clinical Relevance
Clinical relevance is one of the most important aspects of patch testing. Sometimes clinical relevance can only be ascertained weeks after testing — ie, if a patient avoids an allergen within PCPs and, indeed, his/her rash resolves, or if a patient realizes an exposure to an allergen that was not obvious at time of testing. Sometimes strong or extreme reactions simply represent past sensitization and have no bearing on the patient’s present problem. Likewise, at times, a weak reaction can be very clinically relevant and avoiding it can “cure” a patient’s dermatitis.
Some allergens are paradoxical — some patients with paraben allergy will tolerate it on non-dermatitic skin, known as the parabens paradox.20-22 Conversely, lanolin, parabens and other allergens, which are thought to be weak sensitizers, can become allergens in the setting of chronic dermatitis or leg ulcers.22
Many patients with gold allergy on patch testing can wear gold jewelry without developing dermatitis. However, sometimes these patients can transfer allergens from fingers to face and develop eyelid dermatitis, even in the absence of a rash at the jewelry site. In fact, gold is the number 1 eyelid allergen.23 Therefore, in patients with eyelid dermatitis who are positive to gold on patch testing, it is always helpful to ask if they handle their jewelry frequently during the day and explain how this can lead to the transfer of allergens in this manner. The NACDG, however, has removed gold from its standard tray given the high positivity prevalence but low clinical relevance of this allergen.24
Patients who would like to prove clinical relevance of a positive patch test result can perform a repeat open application test (ROAT) with leave-on products. A ROAT consists of application of a product to the same non-dermatitic, 1-cm area near the flexor aspect of the antecubital fossa twice daily for 7 days.25 If redness, papules and/or swelling develop, this proves allergy to the product. There can be false negatives with the ROAT, however, given the application on non-diseased skin, which is a drawback of the test.26
Patient And Provider Expectations
It is important to temper even strong patch test reactions with appropriate expectations. Sometimes dermatitis does not improve despite finding allergens on patch testing and diligent avoidance by a patient, especially in the setting of chronic, occupation-induced hand dermatitis, when even a job change does not cure the dermatitis.27 Since the immune system has memory, even extreme reactions may just represent past sensitization and may not be clinically relevant to a patient’s current problem.
Some patients with recalcitrant generalized eruptions are manifesting reactions to certain allergens that they are ingesting. Such dermatitis is known as systemic contact dermatitis. The allergens listed in Table 2 can be found in foods/ingested items in addition to topical sources.3,28,29
Directing The Patient To Alternatives
After educating patients about what not to use, they must be given suggestions for appropriate alternatives; otherwise, they are not likely to improve. As mentioned above, the ACDS offers members access to CAMP. This program allows physicians to list their patients’ allergens and create a document with products a patient can safely use without their allergens. This type of substitution list is invaluable to treating patients with allergic contact dermatitis. However, patients still need to be instructed to carefully read labels, as many companies have a variety of products, all with very similar names but slightly different ingredients. There may also be occasional formulation changes, so it is important for patients with contact allergens to be diligent label readers.
Recalcitrant Cases
For patients who do not improve with topical avoidance, dietary avoidance of systemic allergens and changing textiles to ones without dyes or formaldehyde are sometimes helpful, in situations of potential systemic allergens or textile (dye or formaldehyde resin) allergens, respectively.
The amount of information provided in a final patch test session can be overwhelming for patients, so a consult letter with a summary of the allergens and avoidance strategies is quite helpful and appreciated by the patient and referring doctor. Patients are usually grateful if the patch testing physician will occasionally review ingredient lists of products not on the CAMP/CARD list; reassuring patients that they can e-mail or fax with questions helps them feel less beleaguered by the whole process.
For those patients who don’t clear after patch testing, there are further evaluations that can be performed. Especially in an older patient with an unexplained persistent eruption, one needs to consider paraneoplastic processes, cutaneous T cell lymphoma and drug eruptions. If biopsy and work-up do not help explain a recalcitrant dermatitis after patch testing, and a paraneoplastic process is ruled out, other therapeutic options such as ultraviolet light therapy and oral immunosuppressant can be considered.
Conclusion
Most patients are very thankful for the time and effort physicians put into educating them about their documented contact allergens. It is extremely rewarding for physicians and healthcare providers to be able to use their “sleuth” skills and cure patients of recalcitrant rashes based on patch test results and education.
Dr. Scheinman is the director of the Contact Dermatitis and Occupational Dermatology Unit and a clinical associate professor of dermatology at Tufts Medical Center in Boston, MA.
Disclosure: Dr. Scheinman has no conflicts of interest or financial disclosures to report.
Dr. Jacob, the Section Editor of Allergen Focus, is Associate Clinical Professor of Medicine and Pediatrics WOS (Dermatology) at the University of California, San Diego.
Disclosure: Dr. Jacob is the principal investigator for Smartchoice USA PREA-2 trial.
Editor's Note: Please see the PDF of this article posted above to see the tables and figures.
Patient education and counseling may be the key to proper allergen avoidance and remission of the dermatitis.
Allergic Contact Dermatitis (ACD) is an important disease that notably affects 14.5 million Americans each year.1 The economic impact of this disease is high in terms of both patient morbidity and loss of income, school and work, not to mention significant expenditures for visits to healthcare providers and for medicaments.1 Once patch testing is performed and a culprit has been identified, education becomes the critical intervention to ensure adherence to an avoidance regimen. With allergen avoidance, remission of the dermatitis often ensues. If the patient is unable to comply with the avoidance regimen, they are at risk for recurrent or sustained dermatitis or progression to a systematized presentation.2,3 In fact, education of the patient often begins before the diagnostic patch test is ever placed. This ensures that the patient has an appropriate understanding of potential outcomes and his or her central role in both the disease and treatment.
During the initial consultation, patients are often taught about the pathophysiology of ACD: its delayed presentation; its relationship with the immune system (sensitization to a chemical and then elicitation of a dermatitis with re-exposure); and its occurrence at any point in time, even to something the patient has been using regularly for a short period of time or even intermittently for years. In certain cases, the other key players, such as irritant contact dermatitis (ICD) and contact urticaria, may be explained via history (not patch testing) and can point to these as the correct diagnosis. It is important to note that ICD, the most prevalent form of contact dermatitis, can, at times, precede or be a concomitant diagnosis with ACD.4,5 Unlike ACD, ICD is not immune-mediated; it occurs secondary to contact with an irritating or abrasive substance. Contact urticaria (wheal and flare reaction), on the other hand, represents the least prevalent form of contact dermatitis. It is important to note that it is an immune-mediated phenomenon whose hallmark is an IgE and mast cell-mediated immediate-type hypersensitivity reaction. We acknowledge this form of hypersensitivity due to the severity of the potential deleterious anaphylactic-type reactions and direct the reader to key sources.6-8
In this section, we highlight ACD and explore top relevant allergens, regional and topic-based dermatitis presentations and clinical tips and pearls for diagnosis and treatment. This edition focuses on education of the patient.
Patient Counseling and Allergen Education in the Patch Test Clinic
Perhaps the most important aspect of the patch testing procedure is patient education, both pre and post patch test. If patients do not understand what they are being tested for, what they need to avoid and where they may encounter their allergen(s), it will be very difficult to ‘cure’ [remit] the contact dermatitis and have them remain clear.
It is essential to start with the basics. Many patients (and some referring physicians and clinical providers) think, erroneously, that patch testing is equivalent to scratch/intradermal testing and that it involves needle testing for items such as pollen, dust, mold and dander. However, patch testing is a reflection of T-cell mediated immunity (delayed type hypersensitivity; type IV immune reaction), which is a completely different test than scratch or intradermal testing. The latter is a reflection of an antibody-mediated, immediate hypersensitivity immune reaction (type I immune reaction) generally causing symptoms such as eye tearing, rhinorrhea and shortness of breath.
Types Of Allergens
The patch test allergens, in general, are found within personal care products used on the skin, hair and nails (preservatives, fragrances, surfactants or emulsifiers, for example) or are in items that come into contact with the skin: metals in jewelry, textile formaldehyde resins, rubber additives in gloves and clothing items, and so on. The cutaneous symptoms typically caused by contact allergens include rashes and sometimes skin swelling. Again, in general, direct contact of an allergen with the skin surface initiates the symptoms, although ingestion or inhalation of an allergen or parenteral exposure can occasionally cause a localized or generalized rash known as systemic contact dermatitis.9
Especially when dealing with occupational contact dermatitis, whether irritant or allergic, it is important for the diagnosing physician to have a plausible hypothesis for how putative allergens or irritants in the workplace would explain a patient’s distribution of dermatitis, whether it is direct contact with a substance (often with hand involvement), airborne exposure or splash exposure. For example, an administrative assistant working at a law office who blames her periumbilical eruption on her workplace and is nickel-allergic on patch testing would not be deemed to have occupational allergic contact dermatitis.
Essential Information Sheets
Many patients are overwhelmed by the names of some of the allergens tested, let alone synonyms and exposure sources – methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) has more syllables than supercalifragilistickexpialidocious. It is therefore helpful to have an educated assistant working with you in the office to review information sheets about allergens with your patients, answer any questions they may have and review product listings of suitable personal care products (PCPs) without their documented allergens. It is essential to have information sheets on tested allergens (paper or electronic copies) to give or e-mail to patients so they may review information at their leisure after the office visit.
Education Strategies
There can be a fair amount of denial, which can be a barrier to patients’ willingness to believe they may be allergic to a favorite cream or lotion. It is very important to patch test for these favorite items with the caveat that, sometimes, an allergen can be diluted when testing to a full product and can lead to a false negative. Certainly, if there’s a positive reaction, it makes a big impression. It is sometimes necessary to reinforce the notion that, since contact allergy is a reflection of delayed type hypersensitivity, a reaction can take place 24 to 48 hours after a product is applied to the skin (or worn, if it’s a textile), and is just not obvious to a patient. In one study, 50% of patients and physicians were unaware that a cosmetic contained a culprit allergen.10 Patients can also be reluctant to accept that they are allergic to products they’ve used for years without a problem. An explanation of the factors that contribute to elicitation of allergic contact dermatitis, including an impaired skin barrier, low environmental humidity and/or prolonged exposure time to an allergen, together with heat, pressure and friction, can help convince a skeptical patient.
It is also extremely convincing to take a photo of patients’ patch test reactions. After seeing an edematous plaque or bullous reaction, patients are more likely to believe they will need to avoid certain products. It is essential to have patients bring in their PCPs on the final patch test day. It is sometimes surprising, to the author, how many “nothings” patients are using on their skin. Circling or underlining documented allergens on a label is an effective education strategy. The author likes to reassure patients that they should not feel bad if almost everything they have been using is not suitable. Patients allergic to the top two cosmetic allergens, formaldehyde-releasing preservatives and fragrance,11 will often still be exposed to these allergens even after switching to numerous different PCPs prior to patch testing. It is vital to stress that they will be receiving a detailed list of products that are safe to use. Otherwise, patients can become overwhelmed and hopeless.
It may be worthwhile to group allergens into categories for your patient. For example, if a patient reacts to quaternium 15, fragrance or MCI/MI, these could be categorized as personal care product-type allergens. It is helpful to refrain from the word “cosmetic” when discussing these allergens with male patients, as some may be insulted if they are told they are allergic to a “cosmetic” allergen. For patients who react to formaldehyde, it is important to review the names of all the formaldehyde-releasing preservatives (FRPs). Patients need to be aware that they will almost never see the word “formaldehyde” on a shampoo or body wash label, but will often find FRPs in these products. Quaternium–15, 2-bromo-2-nitropropane-1,3-diol (bronopol), imidazolidinyl urea (imid urea), diazolidinyl urea and DMDM hydantoin are FRPs found in many shampoos, body washes and lotions. Patients who are formaldehyde-allergic should be familiar with these names. Some corticosteroids contain FRPs, including Ultravate and Halobetasol cream, which contain diazolidinyl urea. Cutivate cream contains imidazolidinyl urea, abbreviated as imid urea.
An excellent resource for exploring functions and synonyms for various multi-syllabic chemicals on a product label is the Council Link on the American Contact Dermatitis Society’s (ACDS) website (www.contactderm.org). This link gives a member physician access to information from the Personal Care Products Council and includes International Cosmetic Ingredient (INCI) names, trade names and functions and structures of chemicals.
The Marks, Elsner and Deleo textbook12 explicitly permits duplication of allergen information sheets for use in clinical practice. These information sheets can be copied, scanned and distributed. Additionally, the ACDS has information sheets available in PDF to members for patient education on their website within the Contact Allergen Management Program (CAMP) link under the Narratives List tab. For a yearly fee, www.preventice.com also offers the Contact Allergen Replacement Database (CARD), which generates lists of safe products patients may use. In addition, there is a free online service called www.mypatchlink.com that patients can be directed to watch videos about allergic contact dermatitis and specific allergens.
Textile Allergy Example
If one is testing only with the TRUE Test patch test, formaldehyde is a very good screening chemical for formaldehyde textile resin allergy; approximately 70% of those with a textile formaldehyde allergy will be detected.13 For a patient with a generalized eruption and formaldehyde allergy on patch testing, such a reaction could represent allergy to clothing formaldehyde resins. Formaldehyde textile resins can be present in permanent press/wrinkle-resistant fabrics, even if 100% cotton or blended fabrics (any natural fiber blended with a synthetic fiber). Suitable fabrics for such patients include 100% soft, wrinkly cotton, silk or linen, 100% polyester, nylon or acrylic.14 In a patient with a generalized eruption who reacts to formaldehyde on patch testing and is not using any PCPs containing FRPs, it is important to consider textile formaldehyde resins as potentially problematic.
P-phenylene diamine (PPD), the main hair dye sensitizer, and black rubber mix (BRM) can serve as screening allergens for textile dye allergy; in one study, PPD and BRM picked up approximately 50% of patients allergic to at least one ingredient of a textile dye mix.15 PPD and BRM reactions are therefore potentially clinically relevant allergens in a patient with generalized dermatitis suggesting a textile-type allergen — even in a patient who does not color his or her hair. It is up to the patch-testing physician to put the pieces of the puzzle together for patients and try to explain their patch test reactions in light of the their history, occupation and distribution of dermatitis.
Fragrance Allergy Example
Most patients are emphatic that they cannot be reacting to fragrance because they do not wear cologne or perfume. Many don’t realize that the causative fragrance allergen is usually present in a personal care product and not necessarily in a cologne or perfume.11 Additionally, many patients may be adamant that all their products are “fragrance free” or “hypoallergenic.” They are unaware that many products marketed as fragrance-free still contain fragrance chemicals (see Table 1). Due to a legal loophole, if a chemical is not used solely to impart an odor to the product, a fragrance chemical can be used in a “fragrance-free” product.16 Rose, lavender, coriander and cardamom are all present in various popular personal care products labeled fragrance-free.17 As such, a consumer with contact allergy really needs to pay special attention to all inactive ingredients in a product and not rely on marketing on the label. Additionally, many patients feel that “all natural” products are beneficial; however, in ancient times, fragrances were made from herbs, roots, flowers, woods and spices,18 and, therefore, patients allergic to fragrance may react to “all natural” products they are using.
Screening allergens for fragrance allergy present on the TRUE Test include fragrance mix I and balsam of Peru. Balsam of Peru (Myroxylon pereirae) is a very complex fragrance resin obtained from wounding a type of tree. Myroxylon pereirae contains more than 200 individual ingredients, including cinnamic acid, cinnamic alcohol, cinnamic aldehyde, benzyl alcohol, benzaldehyde, benzoic acid, isoeugenol, coniferyl alcohol and vanillin, among others.19
Rubber Additive Example
For patients reacting to rubber additives (thiuram mix, black rubber mix, carba mix, mercapto mix), counseling physicians should stress that these MAY be relevant for waistband dermatitis, bra dermatitis (ie, to elastic or foam portions of bras), hand dermatitis (in those wearing rubber gloves) and foot dermatitis (ie, from rubber additives in spongy/foamy portions of shoes and/or adhesives). It is important to note that sometimes patients will only be symptomatic in one location of the body and not every area of exposure. For example, some patients with rubber additive allergens will only have foot dermatitis but not waistband dermatitis, some may have hand dermatitis but not waistband or foot dermatitis and so forth. Pressure, friction, heat and humidity and exposure to irritants, all play a role in the manifestation of allergic contact dermatitis.
Clinical Relevance
Clinical relevance is one of the most important aspects of patch testing. Sometimes clinical relevance can only be ascertained weeks after testing — ie, if a patient avoids an allergen within PCPs and, indeed, his/her rash resolves, or if a patient realizes an exposure to an allergen that was not obvious at time of testing. Sometimes strong or extreme reactions simply represent past sensitization and have no bearing on the patient’s present problem. Likewise, at times, a weak reaction can be very clinically relevant and avoiding it can “cure” a patient’s dermatitis.
Some allergens are paradoxical — some patients with paraben allergy will tolerate it on non-dermatitic skin, known as the parabens paradox.20-22 Conversely, lanolin, parabens and other allergens, which are thought to be weak sensitizers, can become allergens in the setting of chronic dermatitis or leg ulcers.22
Many patients with gold allergy on patch testing can wear gold jewelry without developing dermatitis. However, sometimes these patients can transfer allergens from fingers to face and develop eyelid dermatitis, even in the absence of a rash at the jewelry site. In fact, gold is the number 1 eyelid allergen.23 Therefore, in patients with eyelid dermatitis who are positive to gold on patch testing, it is always helpful to ask if they handle their jewelry frequently during the day and explain how this can lead to the transfer of allergens in this manner. The NACDG, however, has removed gold from its standard tray given the high positivity prevalence but low clinical relevance of this allergen.24
Patients who would like to prove clinical relevance of a positive patch test result can perform a repeat open application test (ROAT) with leave-on products. A ROAT consists of application of a product to the same non-dermatitic, 1-cm area near the flexor aspect of the antecubital fossa twice daily for 7 days.25 If redness, papules and/or swelling develop, this proves allergy to the product. There can be false negatives with the ROAT, however, given the application on non-diseased skin, which is a drawback of the test.26
Patient And Provider Expectations
It is important to temper even strong patch test reactions with appropriate expectations. Sometimes dermatitis does not improve despite finding allergens on patch testing and diligent avoidance by a patient, especially in the setting of chronic, occupation-induced hand dermatitis, when even a job change does not cure the dermatitis.27 Since the immune system has memory, even extreme reactions may just represent past sensitization and may not be clinically relevant to a patient’s current problem.
Some patients with recalcitrant generalized eruptions are manifesting reactions to certain allergens that they are ingesting. Such dermatitis is known as systemic contact dermatitis. The allergens listed in Table 2 can be found in foods/ingested items in addition to topical sources.3,28,29
Directing The Patient To Alternatives
After educating patients about what not to use, they must be given suggestions for appropriate alternatives; otherwise, they are not likely to improve. As mentioned above, the ACDS offers members access to CAMP. This program allows physicians to list their patients’ allergens and create a document with products a patient can safely use without their allergens. This type of substitution list is invaluable to treating patients with allergic contact dermatitis. However, patients still need to be instructed to carefully read labels, as many companies have a variety of products, all with very similar names but slightly different ingredients. There may also be occasional formulation changes, so it is important for patients with contact allergens to be diligent label readers.
Recalcitrant Cases
For patients who do not improve with topical avoidance, dietary avoidance of systemic allergens and changing textiles to ones without dyes or formaldehyde are sometimes helpful, in situations of potential systemic allergens or textile (dye or formaldehyde resin) allergens, respectively.
The amount of information provided in a final patch test session can be overwhelming for patients, so a consult letter with a summary of the allergens and avoidance strategies is quite helpful and appreciated by the patient and referring doctor. Patients are usually grateful if the patch testing physician will occasionally review ingredient lists of products not on the CAMP/CARD list; reassuring patients that they can e-mail or fax with questions helps them feel less beleaguered by the whole process.
For those patients who don’t clear after patch testing, there are further evaluations that can be performed. Especially in an older patient with an unexplained persistent eruption, one needs to consider paraneoplastic processes, cutaneous T cell lymphoma and drug eruptions. If biopsy and work-up do not help explain a recalcitrant dermatitis after patch testing, and a paraneoplastic process is ruled out, other therapeutic options such as ultraviolet light therapy and oral immunosuppressant can be considered.
Conclusion
Most patients are very thankful for the time and effort physicians put into educating them about their documented contact allergens. It is extremely rewarding for physicians and healthcare providers to be able to use their “sleuth” skills and cure patients of recalcitrant rashes based on patch test results and education.
Dr. Scheinman is the director of the Contact Dermatitis and Occupational Dermatology Unit and a clinical associate professor of dermatology at Tufts Medical Center in Boston, MA.
Disclosure: Dr. Scheinman has no conflicts of interest or financial disclosures to report.
Dr. Jacob, the Section Editor of Allergen Focus, is Associate Clinical Professor of Medicine and Pediatrics WOS (Dermatology) at the University of California, San Diego.
Disclosure: Dr. Jacob is the principal investigator for Smartchoice USA PREA-2 trial.
Editor's Note: Please see the PDF of this article posted above to see the tables and figures.
Patient education and counseling may be the key to proper allergen avoidance and remission of the dermatitis.
Allergic Contact Dermatitis (ACD) is an important disease that notably affects 14.5 million Americans each year.1 The economic impact of this disease is high in terms of both patient morbidity and loss of income, school and work, not to mention significant expenditures for visits to healthcare providers and for medicaments.1 Once patch testing is performed and a culprit has been identified, education becomes the critical intervention to ensure adherence to an avoidance regimen. With allergen avoidance, remission of the dermatitis often ensues. If the patient is unable to comply with the avoidance regimen, they are at risk for recurrent or sustained dermatitis or progression to a systematized presentation.2,3 In fact, education of the patient often begins before the diagnostic patch test is ever placed. This ensures that the patient has an appropriate understanding of potential outcomes and his or her central role in both the disease and treatment.
During the initial consultation, patients are often taught about the pathophysiology of ACD: its delayed presentation; its relationship with the immune system (sensitization to a chemical and then elicitation of a dermatitis with re-exposure); and its occurrence at any point in time, even to something the patient has been using regularly for a short period of time or even intermittently for years. In certain cases, the other key players, such as irritant contact dermatitis (ICD) and contact urticaria, may be explained via history (not patch testing) and can point to these as the correct diagnosis. It is important to note that ICD, the most prevalent form of contact dermatitis, can, at times, precede or be a concomitant diagnosis with ACD.4,5 Unlike ACD, ICD is not immune-mediated; it occurs secondary to contact with an irritating or abrasive substance. Contact urticaria (wheal and flare reaction), on the other hand, represents the least prevalent form of contact dermatitis. It is important to note that it is an immune-mediated phenomenon whose hallmark is an IgE and mast cell-mediated immediate-type hypersensitivity reaction. We acknowledge this form of hypersensitivity due to the severity of the potential deleterious anaphylactic-type reactions and direct the reader to key sources.6-8
In this section, we highlight ACD and explore top relevant allergens, regional and topic-based dermatitis presentations and clinical tips and pearls for diagnosis and treatment. This edition focuses on education of the patient.
Patient Counseling and Allergen Education in the Patch Test Clinic
Perhaps the most important aspect of the patch testing procedure is patient education, both pre and post patch test. If patients do not understand what they are being tested for, what they need to avoid and where they may encounter their allergen(s), it will be very difficult to ‘cure’ [remit] the contact dermatitis and have them remain clear.
It is essential to start with the basics. Many patients (and some referring physicians and clinical providers) think, erroneously, that patch testing is equivalent to scratch/intradermal testing and that it involves needle testing for items such as pollen, dust, mold and dander. However, patch testing is a reflection of T-cell mediated immunity (delayed type hypersensitivity; type IV immune reaction), which is a completely different test than scratch or intradermal testing. The latter is a reflection of an antibody-mediated, immediate hypersensitivity immune reaction (type I immune reaction) generally causing symptoms such as eye tearing, rhinorrhea and shortness of breath.
Types Of Allergens
The patch test allergens, in general, are found within personal care products used on the skin, hair and nails (preservatives, fragrances, surfactants or emulsifiers, for example) or are in items that come into contact with the skin: metals in jewelry, textile formaldehyde resins, rubber additives in gloves and clothing items, and so on. The cutaneous symptoms typically caused by contact allergens include rashes and sometimes skin swelling. Again, in general, direct contact of an allergen with the skin surface initiates the symptoms, although ingestion or inhalation of an allergen or parenteral exposure can occasionally cause a localized or generalized rash known as systemic contact dermatitis.9
Especially when dealing with occupational contact dermatitis, whether irritant or allergic, it is important for the diagnosing physician to have a plausible hypothesis for how putative allergens or irritants in the workplace would explain a patient’s distribution of dermatitis, whether it is direct contact with a substance (often with hand involvement), airborne exposure or splash exposure. For example, an administrative assistant working at a law office who blames her periumbilical eruption on her workplace and is nickel-allergic on patch testing would not be deemed to have occupational allergic contact dermatitis.
Essential Information Sheets
Many patients are overwhelmed by the names of some of the allergens tested, let alone synonyms and exposure sources – methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) has more syllables than supercalifragilistickexpialidocious. It is therefore helpful to have an educated assistant working with you in the office to review information sheets about allergens with your patients, answer any questions they may have and review product listings of suitable personal care products (PCPs) without their documented allergens. It is essential to have information sheets on tested allergens (paper or electronic copies) to give or e-mail to patients so they may review information at their leisure after the office visit.
Education Strategies
There can be a fair amount of denial, which can be a barrier to patients’ willingness to believe they may be allergic to a favorite cream or lotion. It is very important to patch test for these favorite items with the caveat that, sometimes, an allergen can be diluted when testing to a full product and can lead to a false negative. Certainly, if there’s a positive reaction, it makes a big impression. It is sometimes necessary to reinforce the notion that, since contact allergy is a reflection of delayed type hypersensitivity, a reaction can take place 24 to 48 hours after a product is applied to the skin (or worn, if it’s a textile), and is just not obvious to a patient. In one study, 50% of patients and physicians were unaware that a cosmetic contained a culprit allergen.10 Patients can also be reluctant to accept that they are allergic to products they’ve used for years without a problem. An explanation of the factors that contribute to elicitation of allergic contact dermatitis, including an impaired skin barrier, low environmental humidity and/or prolonged exposure time to an allergen, together with heat, pressure and friction, can help convince a skeptical patient.
It is also extremely convincing to take a photo of patients’ patch test reactions. After seeing an edematous plaque or bullous reaction, patients are more likely to believe they will need to avoid certain products. It is essential to have patients bring in their PCPs on the final patch test day. It is sometimes surprising, to the author, how many “nothings” patients are using on their skin. Circling or underlining documented allergens on a label is an effective education strategy. The author likes to reassure patients that they should not feel bad if almost everything they have been using is not suitable. Patients allergic to the top two cosmetic allergens, formaldehyde-releasing preservatives and fragrance,11 will often still be exposed to these allergens even after switching to numerous different PCPs prior to patch testing. It is vital to stress that they will be receiving a detailed list of products that are safe to use. Otherwise, patients can become overwhelmed and hopeless.
It may be worthwhile to group allergens into categories for your patient. For example, if a patient reacts to quaternium 15, fragrance or MCI/MI, these could be categorized as personal care product-type allergens. It is helpful to refrain from the word “cosmetic” when discussing these allergens with male patients, as some may be insulted if they are told they are allergic to a “cosmetic” allergen. For patients who react to formaldehyde, it is important to review the names of all the formaldehyde-releasing preservatives (FRPs). Patients need to be aware that they will almost never see the word “formaldehyde” on a shampoo or body wash label, but will often find FRPs in these products. Quaternium–15, 2-bromo-2-nitropropane-1,3-diol (bronopol), imidazolidinyl urea (imid urea), diazolidinyl urea and DMDM hydantoin are FRPs found in many shampoos, body washes and lotions. Patients who are formaldehyde-allergic should be familiar with these names. Some corticosteroids contain FRPs, including Ultravate and Halobetasol cream, which contain diazolidinyl urea. Cutivate cream contains imidazolidinyl urea, abbreviated as imid urea.
An excellent resource for exploring functions and synonyms for various multi-syllabic chemicals on a product label is the Council Link on the American Contact Dermatitis Society’s (ACDS) website (www.contactderm.org). This link gives a member physician access to information from the Personal Care Products Council and includes International Cosmetic Ingredient (INCI) names, trade names and functions and structures of chemicals.
The Marks, Elsner and Deleo textbook12 explicitly permits duplication of allergen information sheets for use in clinical practice. These information sheets can be copied, scanned and distributed. Additionally, the ACDS has information sheets available in PDF to members for patient education on their website within the Contact Allergen Management Program (CAMP) link under the Narratives List tab. For a yearly fee, www.preventice.com also offers the Contact Allergen Replacement Database (CARD), which generates lists of safe products patients may use. In addition, there is a free online service called www.mypatchlink.com that patients can be directed to watch videos about allergic contact dermatitis and specific allergens.
Textile Allergy Example
If one is testing only with the TRUE Test patch test, formaldehyde is a very good screening chemical for formaldehyde textile resin allergy; approximately 70% of those with a textile formaldehyde allergy will be detected.13 For a patient with a generalized eruption and formaldehyde allergy on patch testing, such a reaction could represent allergy to clothing formaldehyde resins. Formaldehyde textile resins can be present in permanent press/wrinkle-resistant fabrics, even if 100% cotton or blended fabrics (any natural fiber blended with a synthetic fiber). Suitable fabrics for such patients include 100% soft, wrinkly cotton, silk or linen, 100% polyester, nylon or acrylic.14 In a patient with a generalized eruption who reacts to formaldehyde on patch testing and is not using any PCPs containing FRPs, it is important to consider textile formaldehyde resins as potentially problematic.
P-phenylene diamine (PPD), the main hair dye sensitizer, and black rubber mix (BRM) can serve as screening allergens for textile dye allergy; in one study, PPD and BRM picked up approximately 50% of patients allergic to at least one ingredient of a textile dye mix.15 PPD and BRM reactions are therefore potentially clinically relevant allergens in a patient with generalized dermatitis suggesting a textile-type allergen — even in a patient who does not color his or her hair. It is up to the patch-testing physician to put the pieces of the puzzle together for patients and try to explain their patch test reactions in light of the their history, occupation and distribution of dermatitis.
Fragrance Allergy Example
Most patients are emphatic that they cannot be reacting to fragrance because they do not wear cologne or perfume. Many don’t realize that the causative fragrance allergen is usually present in a personal care product and not necessarily in a cologne or perfume.11 Additionally, many patients may be adamant that all their products are “fragrance free” or “hypoallergenic.” They are unaware that many products marketed as fragrance-free still contain fragrance chemicals (see Table 1). Due to a legal loophole, if a chemical is not used solely to impart an odor to the product, a fragrance chemical can be used in a “fragrance-free” product.16 Rose, lavender, coriander and cardamom are all present in various popular personal care products labeled fragrance-free.17 As such, a consumer with contact allergy really needs to pay special attention to all inactive ingredients in a product and not rely on marketing on the label. Additionally, many patients feel that “all natural” products are beneficial; however, in ancient times, fragrances were made from herbs, roots, flowers, woods and spices,18 and, therefore, patients allergic to fragrance may react to “all natural” products they are using.
Screening allergens for fragrance allergy present on the TRUE Test include fragrance mix I and balsam of Peru. Balsam of Peru (Myroxylon pereirae) is a very complex fragrance resin obtained from wounding a type of tree. Myroxylon pereirae contains more than 200 individual ingredients, including cinnamic acid, cinnamic alcohol, cinnamic aldehyde, benzyl alcohol, benzaldehyde, benzoic acid, isoeugenol, coniferyl alcohol and vanillin, among others.19
Rubber Additive Example
For patients reacting to rubber additives (thiuram mix, black rubber mix, carba mix, mercapto mix), counseling physicians should stress that these MAY be relevant for waistband dermatitis, bra dermatitis (ie, to elastic or foam portions of bras), hand dermatitis (in those wearing rubber gloves) and foot dermatitis (ie, from rubber additives in spongy/foamy portions of shoes and/or adhesives). It is important to note that sometimes patients will only be symptomatic in one location of the body and not every area of exposure. For example, some patients with rubber additive allergens will only have foot dermatitis but not waistband dermatitis, some may have hand dermatitis but not waistband or foot dermatitis and so forth. Pressure, friction, heat and humidity and exposure to irritants, all play a role in the manifestation of allergic contact dermatitis.
Clinical Relevance
Clinical relevance is one of the most important aspects of patch testing. Sometimes clinical relevance can only be ascertained weeks after testing — ie, if a patient avoids an allergen within PCPs and, indeed, his/her rash resolves, or if a patient realizes an exposure to an allergen that was not obvious at time of testing. Sometimes strong or extreme reactions simply represent past sensitization and have no bearing on the patient’s present problem. Likewise, at times, a weak reaction can be very clinically relevant and avoiding it can “cure” a patient’s dermatitis.
Some allergens are paradoxical — some patients with paraben allergy will tolerate it on non-dermatitic skin, known as the parabens paradox.20-22 Conversely, lanolin, parabens and other allergens, which are thought to be weak sensitizers, can become allergens in the setting of chronic dermatitis or leg ulcers.22
Many patients with gold allergy on patch testing can wear gold jewelry without developing dermatitis. However, sometimes these patients can transfer allergens from fingers to face and develop eyelid dermatitis, even in the absence of a rash at the jewelry site. In fact, gold is the number 1 eyelid allergen.23 Therefore, in patients with eyelid dermatitis who are positive to gold on patch testing, it is always helpful to ask if they handle their jewelry frequently during the day and explain how this can lead to the transfer of allergens in this manner. The NACDG, however, has removed gold from its standard tray given the high positivity prevalence but low clinical relevance of this allergen.24
Patients who would like to prove clinical relevance of a positive patch test result can perform a repeat open application test (ROAT) with leave-on products. A ROAT consists of application of a product to the same non-dermatitic, 1-cm area near the flexor aspect of the antecubital fossa twice daily for 7 days.25 If redness, papules and/or swelling develop, this proves allergy to the product. There can be false negatives with the ROAT, however, given the application on non-diseased skin, which is a drawback of the test.26
Patient And Provider Expectations
It is important to temper even strong patch test reactions with appropriate expectations. Sometimes dermatitis does not improve despite finding allergens on patch testing and diligent avoidance by a patient, especially in the setting of chronic, occupation-induced hand dermatitis, when even a job change does not cure the dermatitis.27 Since the immune system has memory, even extreme reactions may just represent past sensitization and may not be clinically relevant to a patient’s current problem.
Some patients with recalcitrant generalized eruptions are manifesting reactions to certain allergens that they are ingesting. Such dermatitis is known as systemic contact dermatitis. The allergens listed in Table 2 can be found in foods/ingested items in addition to topical sources.3,28,29
Directing The Patient To Alternatives
After educating patients about what not to use, they must be given suggestions for appropriate alternatives; otherwise, they are not likely to improve. As mentioned above, the ACDS offers members access to CAMP. This program allows physicians to list their patients’ allergens and create a document with products a patient can safely use without their allergens. This type of substitution list is invaluable to treating patients with allergic contact dermatitis. However, patients still need to be instructed to carefully read labels, as many companies have a variety of products, all with very similar names but slightly different ingredients. There may also be occasional formulation changes, so it is important for patients with contact allergens to be diligent label readers.
Recalcitrant Cases
For patients who do not improve with topical avoidance, dietary avoidance of systemic allergens and changing textiles to ones without dyes or formaldehyde are sometimes helpful, in situations of potential systemic allergens or textile (dye or formaldehyde resin) allergens, respectively.
The amount of information provided in a final patch test session can be overwhelming for patients, so a consult letter with a summary of the allergens and avoidance strategies is quite helpful and appreciated by the patient and referring doctor. Patients are usually grateful if the patch testing physician will occasionally review ingredient lists of products not on the CAMP/CARD list; reassuring patients that they can e-mail or fax with questions helps them feel less beleaguered by the whole process.
For those patients who don’t clear after patch testing, there are further evaluations that can be performed. Especially in an older patient with an unexplained persistent eruption, one needs to consider paraneoplastic processes, cutaneous T cell lymphoma and drug eruptions. If biopsy and work-up do not help explain a recalcitrant dermatitis after patch testing, and a paraneoplastic process is ruled out, other therapeutic options such as ultraviolet light therapy and oral immunosuppressant can be considered.
Conclusion
Most patients are very thankful for the time and effort physicians put into educating them about their documented contact allergens. It is extremely rewarding for physicians and healthcare providers to be able to use their “sleuth” skills and cure patients of recalcitrant rashes based on patch test results and education.
Dr. Scheinman is the director of the Contact Dermatitis and Occupational Dermatology Unit and a clinical associate professor of dermatology at Tufts Medical Center in Boston, MA.
Disclosure: Dr. Scheinman has no conflicts of interest or financial disclosures to report.
Dr. Jacob, the Section Editor of Allergen Focus, is Associate Clinical Professor of Medicine and Pediatrics WOS (Dermatology) at the University of California, San Diego.
Disclosure: Dr. Jacob is the principal investigator for Smartchoice USA PREA-2 trial.
