The widespread use of TNF antagonists in recent years has led to the recognition of paradoxical adverse effects, defined as the onset or exacerbation of disorders that are usually improved by TNF antagonists. Cutaneous psoriasis is an example, of which several cases have been reported.

To identify cases of psoriasis onset or exacerbation during TNF antagonist therapy and to look for potential predictive factors.

We retrospectively reviewed cases of psoriasis onset or exacerbation during TNF antagonist therapy. For each case we recorded the following data: age, sex, underlying disease, nature of the TNF antagonist, effectiveness in improving the underlying disease, history of psoriasis in the patient or family, time to psoriasis development, type of psoriasis (confirmed by an experienced dermatologist), concomitant treatments, whether the TNF antagonist was stopped or continued, and the outcome of the psoriasis. These data were compared to those in the literature.

We identified 12 patients, six men and six women, with a mean age of 45.5 years. The TNF antagonist was adalimumab in four patients, etanercept in six patients, and infliximab in two patients. The underlying disease was ankylosing spondylitis in six cases, rheumatoid arthritis in four, and psoriatic arthritis in two. Mean time from treatment initiation to psoriasis was 4.1 months (range, 1–15 months). A previous history of psoriasis in the patient was noted in six cases, including four of the six patients taking etanercept. TNF antagonist therapy was effective on the underlying disease in 11 of the 12 patients. The drug was discontinued in five patients, of whom four experienced resolution of their psoriasis. In the remaining seven patients, the drug was continued and the skin lesions remained unchanged. Most of the patients had psoriasis vulgaris (plaque psoriasis); palmoplantar pustulosis was a feature in five patients.

Over 40 cases of psoriasis onset or exacerbation during TNF antagonist therapy have been reported in the literature. The prevalence of this adverse effect has been estimated at 1.5–5% of patients taking TNF antagonists. The findings from our case series are consistent with data in the literature. Psoriasis is a class effect that has been reported with all the currently available TNF antagonists. The skin lesions develop within the first few months of therapy. Patients with a wide range of underlying diseases can be affected. Palmoplantar pustulosis is a common feature. A previous history of psoriasis seems more common in patients who experience psoriasis onset or exacerbation during etanercept therapy (four of six patients in our study and 55% in the literature); thus, previous psoriasis may be a risk factor for psoriasis exacerbation during etanercept therapy.