Characterizing the adverse dermatologic effects of hydroxychloroquine: a systematic review.

ABSTRACT: Background Hydroxychloroquine is associated with myriad adverse dermatologic effects, most of which are poorly characterized by the literature, with unknown frequencies and risk factors. Objective To conduct a systematic review on the adverse dermatologic effects and predisposing factors of hydroxychloroquine toxicity. Results Ninety-four articles were included for review comprising a total of 689 adverse dermatologic side effects. A total of 21 unique dermatologic reactions were reported, most commonly: drug eruption or rash (358 cases), cutaneous hyperpigmentation (116), pruritis (62), acute generalized exanthematous pustulosis (27), Stevens-Johnson syndrome or toxic epidermal necrolysis (26), hair loss (12), and stomatitis (11). Almost all underlying conditions were rheumatologic or autoimmune in nature, composed primarily of lupus erythematous (72% of all cases) and rheumatoid arthritis (14%). The range of reported mean cumulative dosages was wide, with some adverse reactions found after as little as 3 g or as much as 2500 g. Conclusion Though hydroxychloroquine is generally well-tolerated, dermatologic side effects involving the skin, hair, or nails are a frequent and significant complication. The majority of these reactions occurred after treating autoimmune conditions, often manifesting on the skin after a wide range of cumulative dosages.