Late-Onset Rash from Irbesartan: An Immunological Reaction

Abstract

Cutaneous delayed reactions to antihypertensive drugs have been described in a limited number of case reports but the mechanisms remain mostly unknown. We report the case of a 60-year-old female patient with a 3-week history of an itchy erythematous maculopapular eruption. Although the patient was polymedicated, irbesartan was the most likely culprit. Patch tests and a lymphocyte transformation test to irbesartan were both positive, which was useful for diagnosis and suggested an immunological reaction. No new lesions appeared after irbesartan was stopped or after the introduction of candesartan. Despite its similar chemical structure, candesartan may be tried in patients allergic to irbesartan.

Keywords

• Irbesartan allergy
• maculopapular rash
• patch tests
• lymphocyte transformation test
• drug reaction