Toenail Psoriasis during Ustekinumab Therapy: Results and Limitations

BACKGROUND: Nail psoriasis is a common clinically significant symptom of psoriasis. However, few studies have focused on the characteristics and course of toenail psoriasis. OBJECTIVE: To investigate the treatment response of toenail psoriasis during a 52-week period of ustekinumab use. METHODS: Patients were evaluated using the Nail Psoriasis Severity Index (NAPSI) at every injection visit. NAPSI score changes throughout the treatment were analyzed. The treatment response in each toenail and each NAPSI characteristic was also analyzed. RESULTS: A total of 22 patients with chronic plaque psoriasis with concomitant toenail psoriasis were examined. Several characteristics such as ridging or onychomycosis that mimic psoriasis or hinder the evaluation were identified. NAPSI significantly improved during the treatment (p<0.05). The big and second toes were significantly improved after 52 weeks of ustekinumab treatment (p<0.05). Pitting and oil-drop discoloration were the only two characteristics that showed significant changes post-treatment (p<0.05). CONCLUSION: Ustekinumab proved to be efficacious in treating toenail psoriasis. Because of the factors that hinder the NAPSI scoring, only NAPSI scores of the first and second toes can be used.