Hydroxychloroquine effects on psoriasis: A systematic review and a cautionary note for COVID-19 treatment

Background: While evidence suggests that hydroxychloroquine (HCQ) may decrease the viral load in patients with a COVID-19 infection, a number of case reports indicate adverse dermatologic effects of this potential treatment. Objective: To conduct a systematic review of previously reported cases of psoriasis onset, exacerbation, or relapse after HCQ treatment. Methods: Embase and MEDLINE were comprehensively searched for original studies examining adverse effects of HCQ treatment related to psoriasis. Participant demographics and details of HCQ administration and psoriasis diagnosis were extracted from 15 articles representing 18 patients. Results: Women accounted for a significantly larger number of cases of psoriasis compared with men and unreported sex (14 [77.8%] vs 2 [11.1%] vs 2 [11.1%], respectively). In addition, 50% (n = 9) of the patients did not have a history of psoriasis before taking HCQ. Of the 18 patients, 9 (50.0%) experienced de novo psoriasis, 5 (27.8%) experienced exacerbation of psoriatic symptoms, and 4 (22.2%) had a relapse of psoriasis after HCQ administration. Conclusion: HCQ treatment may result in induction, exacerbation, or relapse of psoriasis. Monitoring for adverse effects of HCQ treatment is necessary, and clinical trials are essential in characterizing the safety profile of HCQ use in patients with a COVID-19 infection.