Abstract: 【Abstract】 To report 3 cases of acute generalized exanthematous pustulosis （AGEP） caused by hydroxychloroquine. All three patients were females, aged 23, 30, and 28 years respectively. In cases 1 and 3, the rashes appeared 4 days and 12 days after the treatment with hydroxychloroquine for systemic lupus erythematosus; case 2, who was 8 weeks pregnant, developed rashes 10 days after starting hydroxychloroquine treatment for antiphospholipid syndrome. All the 3 patients had high fever, and clinically presented with generalized round or oval-shaped edematous erythema on the face, neck, trunk and limbs, covered with a large number of pinhead-sized pustules, and with multiple erythema multiforme-like lesions on the trunk and both upper limbs, including targetoid lesions. Mutations in the IL36RN gene were identified in all the 3 patients: a homozygous mutation c.115+6T>C in the IL36RN gene was found in case 1, and her parents were heterozygous carriers; case 2 inherited the heterozygous mutation c.115+6T>C in the IL36RN gene from her mother; the heterozygous mutation c.115+6T>C found in case 3 was a de novo mutation. A diagnosis of AGEP was made. Cases 1 and 2 received subcutaneous injections of adalimumab in addition to the treatment of their underlying diseases, and skin lesions markedly regressed after 1 week of treatment; case 3 was treated with high-dose glucocorticoids, and lesions subsided after 4 weeks; no significant adverse reactions were observed in cases 1 and 2, however, femoral head necrosis was noted in case 3. During a follow-up period of 42 months, none of the patients experienced a recurrence, and case 2 gave birth to a healthy baby boy after 8-month treatment.

Key words: Acute Generalized Exanthematous Pustulosis, Hydroxychloroquine, IL36RN gene, Adalimumab