Nail psoriasis is not as uncommon as some patients with psoriasis may believe.
Nail psoriasis is not uncommon, affecting as many as 80% of patients with psoriasis. In 6% of cases, its lesions may be the only manifestation of psoriasis, and it is more common in men than women. Recognizing nail psoriasis is important because it is an indicator of severe disease and is implicated in early onset of psoriasis and psoriatic arthritis (PsA). “Accordingly, it can also result in significant functional impairment and reduced quality of life,” investigators wrote in a review published in the May 2022 edition of ACTAS Dermo-Sifiliográficas.1
In the review, Elena Canal-García, MD, of the Department of Dermatology at Hospital Universitari Arnau de Vilanova in Lleida, Spain et al listed the following ways clinical presentation of nail psoriasis varies based on location1:
Canal-García et al noted that “Temiz et al recently showed that [patients with psoriasis] were significantly more likely to have nail psoriasis when they smoked, and they also reported a greater need for systemic therapy among smokers.”1,2
PsA is a common comorbidity of nail psoriasis, with investigators reporting an approximate prevalence of 20%. Patients with nail psoriasis are more likely to experience PsA compared with patients who only have the cutaneous form of the disease.
Patients with nail psoriasis may also have onychomycosis, a fungal infection. Some study results found a higher prevalence of this infection in patients with nail psoriasis.3
According to the authors, diagnosing nail psoriasis can be challenging. They recommended standardized assessment using scales such as the Nail Psoriasis Severity Index (NAPSI), the modified NAPSI, and the Physician’s Global Assessment of Fingernail Psoriasis. Recommended diagnostic tools include dermoscopy and ultrasound to assess severity. In addition, providers must pay careful attention to differential diagnosis. “Clinical manifestations similar to those seen in nail psoriasis can be caused by a range of infectious, autoimmune, and idiopathic diseases and trauma. A thorough clinical history and examination of all 20 nails is essential for reaching a correct diagnosis,” Canal-García et al wrote.1
Treatments for nail psoriasis include systemic therapy. There have been few randomized clinical trials conducted for systemic therapy, but there is encouraging data available on acitretin, methotrexate, cyclosporine, and apremilast (Otezla).1
Investigators reported that many biologics have shown good results in managing nail psoriasis, although results tend to be slower than cutaneous psoriasis, with fingernails having faster results than toenails. In a meta-analysis that compared 6 biologics from 7 clinical trials, (all of which included patients with moderate to severe psoriasis with nail involvement), the study’s end point was complete resolution of nail symptoms at weeks 24 to 26 using NAPSI, modified NAPSI, or physician global assessment of 0.1,4 “Ixekizumab was associated with the greatest likelihood of achieving complete response (46.5%), followed by brodalumab (37%), adalimumab (28.3%), guselkumab (27.7%), ustekinumab (20.8%), and infliximab (0.8%),” investigators reported.1,4
In addition to systemic and biologic treatments, the authors also examined topical therapies, including corticosteroids, vitamin D derivatives, calcineurin inhibitors, and tazarotene. All of these topicals seem to be effective, but each has specific instructions and adverse effects. Intralesional injections of corticosteroids “are the only intralesional treatments that have shown acceptable results in nail psoriasis,” according to the authors.1
The authors recommended that nail psoriasis treatment be individualized, “according to the number of nails involved, the part of the nail or nails affected, and the presence of concomitant nail and/or joint involvement.”1