Immediate-type allergy by occupational exposure to didecyl dimethyl ammonium chloride

Didecyl dimethyl ammonium chloride ( DDAC, CAS [ Chemical Abstracts Service] number 7173- 51- 5), a quaternary ammonium compound ( QAC), is a detergent - disinfectant used on floors, walls, and surfaces; it is bactericidal, viricidal, and active against human immunodeficiency virus 1 ( 1) ( Fig. 1). Contact dermatitis from QACs is well known, and also, occupational asthma caused by them has been described ( 2, 3). Allergic reactions because of DDAC are uncommon. Only 2 cases of occupational contact dermatitis ( 4, 5) have been reported. Immediate- type reactions to DDAC have not hitherto been reported. We present a case of contact urticaria, angioedema, and asthma from occupational exposure to DDAC.