When A Patient Presents With Thick, Yellow Toenails And A Rash On Both Feet

An 80-year-old Caucasian presents to the office complaining of thick, yellow, unsightly and sometimes painful toenails. The patient, a retired RN, has had a history of a rash affecting both feet. The rash is sometimes pruritic and sometimes not. She has tried applying topical antifungals to her toenails without success. However, antifungal creams have sometimes helped her skin condition.

   The patient does not have the condition on her hands or fingernails. She has not been exposed to any harsh chemicals. She has not had trauma to her toes. She wears “good” orthopedic Oxford type shoes or open-toe shoes. The patient does complain of occasional pain of the small joints of her fingers and toes. She has not been treated for cancer.

   Upon the physical examination, I noted dystrophic, yellow, streaky, crumbly toenails. The skin of the plantar aspect of both feet was scaly with some erythema. There was no pitting of the toe or fingernails. She did display a rash on her elbows that was somewhat scaly. The patient had some swelling of the distal interphalangeal joints of the lesser toes. There were no vesicles or weeping wounds. Her vital signs were normal.

Key Questions To Consider

1. What would you include in your differential diagnosis?
2. What diagnostic tests would you perform?
3. What essential questions would you pose to this patient?
4. What is your working diagnosis?
5. How would you treat this condition?

Answering The Key Diagnostic Questions

1. Psoriasis, pityriasis rubra pilaris, traumatic onychodystrophy, bacterial infection, nail bed tumors, yellow nail syndrome, idiopathic onycholysis and paronychia congenita.
2. KOH, periodic acid Schiff (PAS) stain and fungal culture.
3. Have you had any history of a rash behind your ears, on the front of your knees or elbows?
4. The most likely diagnosis is psoriasis. However, the PAS stain was positive. She has psoriasis and onychomycosis.
5. There are several treatments for psoriasis. However, the best treatment of her psoriatic nails would be periodic debridement of the nails.

A Guide To Making The Differential Diagnosis

As I noted previously, there are a number of possible differential diagnoses for this patient.1

   Lichen planus. With this condition, it is common to see pruritic, papular eruptions with a polygonal shape and purple color. Individual lesions usually have a fine scaly surface with white striations or white puncta. Alternately, clinicians may see larger, coalesced lesions that are 4 to 5 mm in diameter. Clinicians may also see the development of lichen planus on the flexor surfaces of the upper extremities, the ankles, the anterior aspect of the lower legs, the lumbar area, the genitalia and the mucous membranes.2,3

   Pityriasis rubra pilaris. In adult acute onset type 1 pityriasis rubra pilaris, nail involvement usually presents as distal subungual hyperkeratosis with moderate thickening of the nail bed, splinter hemorrhages and longitudinal ridging.

   Traumatic onychodystrophy. This typically occurs in patients involved in high toe impact sports such as running, tennis, racquetball and similar type sports.

   Bacterial infection. Bacterial infections may cause onycholysis and mimic the onycholysis that sometimes occurs with onychomycosis.

   Nail bed tumors. Some nail bed tumors or subungual exostosis may cause dystrophy of the nail, mimicking onychomycosis.

   Yellow nail syndrome. Yellow nail syndrome is a rare disorder of the nail that usually accompanies lymphedema. It may also be associated with recurrent pleural effusions and less commonly bronchiectasis, chronic bronchitis and sinus infections. The nails are slow growing and appear to have stopped growing. The nails mainly remain smooth but there may be cross ridging and onycholysis.

   Idiopathic onycholysis. This condition occurs more frequently in women and is possibly caused by the same conditions that cause chronic paronychia. In predisposed individuals, frequent contact with water and irritants damages the distal portion of the nail bed.

   Paronychia congenita. Dystrophic, thickened nails and focal palmoplantar keratoderma are commonly associated with this rare condition.4

What You Should Know About Psoriatic Nail Disease

Psoriatic nails reportedly occur in 10 to 55 percent of patients with psoriasis. It occurs in less than 5 percent of those with no other findings of psoriasis.1 Some of the key physical findings in psoriatic nail disease include oil drop or salmon patch lesions of the nail bed, pitting of the proximal nail matrix, Beau’s lines of the proximal nail matrix, leukonychia of the mid-matrix, spotted lunula of the distal matrix or splinter hemorrhage.5

A Closer Look At Treatment Results

Given that this patient had a history of both psoriatic nail disease and onychomycosis, I advised her that even if she received treatment for onychomycosis, her psoriasis would most likely continue to produce the same dystrophic, unsightly nails for which she was seeking treatment. I offered her periodic debridement of her nails, oral antifungal therapy or the 1064 nm Yag laser treatment of onychomycosis. She elected to proceed with the laser treatment.

   Following two laser treatments, she demonstrated significant improvement of her nail condition. However, 11 months after treatment, she had a psoriatic flare-up and some of her nails demonstrated regression. After one more laser treatment, I recommended that she not continue with the laser treatment but return for periodic maintenance care.

   In regard to topical treatments available for psoriatic nails, one may consider high potency corticosteroids such as 5 fluorouracil topical 1% solution or 5% cream (Efudex, Valeant Pharmaceuticals) applied twice daily to the matrix area for six months. Other options include psoralen plus ultraviolet light A (PUVA) or triamcinolone acetonide (Kenalog, Bristol-Myers Squibb) suspension of 2.5 mg per cc into the proximal nail fold, which one may administer every four to six weeks.

   Dr. Uro is in private practice in Sacramento, Calif. He is a past member of the medical advisory board for Patholase. Dr. Uro has disclosed that he is a speaker for Cutera and is currently involved in a retrospective study for the company’s Genesis Plus laser device.

References
1. Elewski BE. Onychomycosis: pathogenesis, diagnosis and management, Clin Microbiol Rev. 1998; 11(3):415-429.
2. Chuang TY. Lichen planus. https://emedicine.medscape.com/article/1123213-overview . Published June 23, 2011. Accessed January 10, 2012.
3. Dockery GD, Bakotic B. What you should know about lichen planus. Pod Today 2007;20(6):52-60.
4. George SJ. Pachyonychia congenital. https://emedicine.medscape.com/article/1106169-overview . Published August 9, 2010. Accessed January 10, 2012.
5. Li C. Nail psoriasis. https://emedicine.medscape.com/article/1107949-overview . Published March 29, 2011. Accessed January 10, 2012.