Systemic therapy for psoriasis and the risk of cutaneous infections.

Systemic treatments are important for patients with moderate-to-severe psoriasis; however, they may occasionally cause adverse infectious events. Although the risk of severe infections with psoriatic treatments is well established, little is known about cutaneous infections. Therefore, we studied the frequency of cutaneous infections in patients with psoriasis who underwent biologic treatment. A total of 878 patients (237 females and 641 males) were analyzed in this follow-up survey conducted in 2020 and based on the Western Japan Psoriasis Registry. The observed skin phenotypes were psoriasis vulgaris (83.3%), pustular psoriasis (7.5%), and psoriatic arthritis (28.9%). The most frequently prescribed systemic drug was apremilast (11.3%), followed by ixekizumab (11.0%), risankizumab (10.9%), and secukinumab (10.4%). The incidence of cutaneous bacterial infections was 12 (1.37% of the total patients), with cellulitis being the most common (8/12, 67%). The incidence of viral infections was 11 (1.25%) including the most common, herpes zoster (9/11, 82%); and that of fungal infections was 45 (5.13%) including 33 (73%) and seven (16%) patients with trichophytosis and oral candidiasis, respectively. Multivariate analysis revealed that cutaneous bacterial infections were frequently observed in patients receiving tumor necrosis factor-α (odds raio [OR] 9.917, 95% confidence interval [CI] 2.069-47.572, p = 0.004) and interleukin (IL)-17 (OR 10.798, 95% CI 2.35-49.616, p = 0.002) inhibitor treatments. A history of otitis media and treatment with oral medications (OR 4.50, 95% CI 1.281-15.804, p = 0.019 and OR 3.80, 95% CI 1.141-12.679, p = 0.03 respectively) were associated with a higher ORs for cutaneous viral infections. Furthermore, age and use of IL-17 inhibitors were associated with elevated ORs for fungal infections. In conclusion, our study reveals that systemic therapies may increase the risk of cutaneous viral infections. Therefore, dermatologists should exercise caution in this regard.