Simple dose-escalation regimen for hydroxychloroquine-induced hypersensitivity reaction in patients with systemic lupus erythematosus enabled treatment resumption.

Objective: This study aimed to investigate the risk factors of hydroxychloroquine (HCQ)-induced hypersensitivity in patients with systemic lupus erythematosus (SLE) and to propose a simple dose-escalation regimen in cases of mild HCQ-induced hypersensitivity. Methods: We identified patients with SLE who started HCQ between 2009 and 2018 and cases of HCQ-induced hypersensitivity by reviewing the electronic medical charts. A simple dose-escalation regimen, starting at 40 mg/day with weekly increments of 40 mg/day to 200 mg/day, was used in patients with HCQ-induced hypersensitivity who did not require hospitalization or systemic steroid therapy. We then compared the clinical parameters of patients with and without HCQ-induced hypersensitivity and evaluated the success of our dose-escalation regimen. Results: We enrolled 302 patients with SLE and identified 25 cases of HCQ-induced eruption (8.3%). The mean Naranjo score of these patients was 5.1 ± 1.4 (min 3, max 8), and all 25 patients received a 'possible' (9) or 'probable' (16) score. A mild, generalized, maculopapular rash occurred in 24 patients, and urticaria occurred in one patient at 24 days (interquartile range 15–40 days) after the start of treatment. The proportion of cyclophosphamide use, glucocorticoid consisting of prednisolone 20 mg/day or more, and initiation of SMX-TMP within 28 days were higher in patients with skin eruptions. On multivariate analysis, only cyclophosphamide use was identified as a risk factor of HCQ-induced hypersensitivity (odds ratio = 12.3 (95% confidential interval 1.4–14.3)). Thirteen of the 14 patients on the dose-escalation regimen (92.9%) tolerated continued HCQ treatment. One patient re-experienced eruptions on day 10 day after starting HCQ. Conclusions: Mild late reactions are common in HCQ-induced hypersensitivity. A simpler dose-escalation regimen enables safe and easier reintroduction of HCQ but should not be applied to patients with immediate reactions or moderate late reactions. [ABSTRACT FROM AUTHOR]