Allergic Skin Rash Caused by Iguratimod: A Report of Two Cases

Iguratimod has been used in the treatment of rheumatoid arthritis and Sjogren's syndrome (SS). Herein, we report two cases of skin allergic reactions caused by iguratimod in our hospital. Case 1 was a woman with SS who developed diffuse pruritus erythema after three weeks of combination therapy of hydroxychloroquine (HCQ) and iguratimod. When the patient was again prescribed iguratimod after the rash subsided, the pruritus erythema reappeared. Case 2 was a 23-year-old girl treated with prednisone, HCQ, and mycophenolate mofetil for systemic lupus erythematosus and SS. In the follow-up treatment, mycophenolate mofetil was replaced by iguratimod. On the 20th day of treatment, a pruritic erythematous maculopapular rash appeared. To the best of our knowledge, this is the first study to report the characteristics of an allergic rash caused by iguratimod. It is better to administer HCQ and iguratimod successively rather than simultaneously to a patient.