Rare case report of rash associated with risperidone long-acting injection

Skin rash is listed by the manufacturer as one of the adverse events that may be associated with risperidone long-acting injection (RLAI). An erythematous rash is described as an infrequent occurrence. The following is a case of a 26-year-old male who developed a diffuse erythematous and maculopapular skin rash on both arms after initiation of RLAI treatment. Previous exposure to oral risperidone was uneventful. Photographs of the rash are included. RLAI treatment was discontinued and diphenhydramine was prescribed. The rash responded to these interventions and was completely gone in 3 weeks. A re-challenge with oral risperidone produced no rash and was clinically effective. A literature review reveals few cases of RLAI treatment with rash and none including an uneventful oral risperidone rechallenge. A consideration of etiologies must include a reaction to an ingredient within the solute or delivery system and becomes an important clinical consideration in treatment planning.