Louise Gagnon is a medical writer and editor based in Oakville, Ontario, Canada.
Systemic therapies, particularly anti-tumor necrosis factor (TNF) agents, are an appropriate course of therapy for patients with nail psoriasis.
New York - Systemic therapies that are effective in treating plaque psoriasis of the skin are also effective in treating nail psoriasis, says Bruce Strober, M.D., Ph.D., assistant professor, New York University, New York.
Numerous features, such as pitting and longitudinal ridges in the fingernails and hyperkeratosis, onychorrhexis and discoloration of the nail plates on the toenails, typify nail psoriasis, says Dr. Strober, adding that nail psoriasis presents with many different features.
Nail psoriasis often presents in patients with moderate-to-severe plaque psoriasis, he says, estimating that 75 percent of patients with moderate-to-severe psoriasis display psoriatic nails.
The outcome with intralesional corticosteroids has been variable using both needle and needleless injector devices.
"It would be quite painful if the injections are made to multiple nails," Dr. Strober says.
Dr. Strober, a believer in the potential efficacy of this approach, questions the practicality of this modality in a real-world setting.
A literature review examining the use of cyclosporine to treat psoriatic nails reveals one open-label study of 16 patients in which 10 of the patients experienced significant improvement.
The study was not rigorous in that it did not describe the duration of therapy or the severity of nail disease, Dr. Strober says, but other studies evaluating cyclosporine more rigorously have shown convincing efficacy.
Dr. Strober suggests that an appropriate course of therapy for patients with nail psoriasis is to use systemic therapies, particularly tumor necrosis factor (TNF) blockers, which have been approved for skin psoriasis, such as infliximab, adalimumab and etanercept.
"The take-home message for dermatologists is that very good skin drugs often make very good nail drugs," Dr. Strober says.
"But it is rare that I will use these drugs solely for nail disease without the presence of significant skin disease and/or the presence of psoriatic arthritis.
"It is important to remember that many patients with psoriatic nail disease also suffer from psoriatic arthritis," he says.
Weaker skin drugs often are weaker nail drugs, Dr. Strober says. He cites that an open-label, retrospective photographic analysis of psoriatic nail disease evaluating the effects of alefacept on nail disease found inconsistent efficacy, even in those patients who displayed improvement in their skin disease.
A double-blinded, randomized, multicenter trial of moderate-to-severe plaque psoriasis examined the impact of etanercept on nail disease.
A total of 58 of 618 patients, 27 of whom received placebo and 31 of whom received etanercept, had photos available that could be judged at baseline and at week 12. Patients on the active compound had an improvement at week 12, while those on placebo experienced a worsening of their condition.
Another trial with the biologic therapy infliximab included patients who had skin psoriasis, and the majority also had nail psoriasis. Investigators observed significant nail improvement in patients treated with infliximab that wasn't observed in the placebo-treated group.
There is a subset of patients with psoriatic arthritis who suffer from psoriatic onycho-pachydermo periostitis (POPP), a condition characterized by psoriatic onychodystrophy. In this setting, adalimumab has been shown effective for the nail disease.
While a minority of patients may have significant nail psoriasis with mild skin disease, those patients may be candidates for systemic therapy if they suggest that their quality of life is diminished by the condition, according to Dr. Strober.
At present, there are no data available on the efficacy of ustekinumab - one of the up-and-coming biological therapies available in the United States for skin psoriasis - to treat nail psoriasis, Dr. Strober adds.
Disclosure: Dr. Strober is a member of the advisory boards for Abbott, Amgen, Centocor, Wyeth, Galderma and Stiefel. He is a consultant for Abbott, Amgen, Wyeth, Centocor, Pfizer, Novo Nordisk, Celgene, Roche, Yaupon and Galderma. He has received honoraria from Abbott, Amgen, Astellas, Centocor and Wyeth.