Angioedema‐like contact dermatitis due to methylisothiazolinone in a mouthwash

Abstract

A 46-year-old atopic woman presented with a 4 month history of recurrent angioedema of her mouth and lips, without respiratory symptoms or wheals (Figure 1); each episode lasted about 24-48 h. Patch tests with the SIDAPA (Società Italiana di DermatologiaAllergologica Professionale e Ambientale) baseline series (SmartPractice, Rome, Italy) were performed. Patch test chambers (Van der Bend, Brielle, The Netherlands) were applied on the upper part of the patient's back.Readings at D2 and D4, according to Italian guidelines, showed positive reaction to potassium dichromate 0.5%, (+/+),