Patch Testing to Chlorhexidine Digluconate, 1% Aqueous: North American Contact Dermatitis Group Experience, 2015-2020.

Chlorhexidine is an antiseptic that may cause allergic contact dermatitis. To describe the epidemiology of chlorhexidine allergy and characterize positive patch test reactions. This retrospective study analyzed patients patch tested to chlorhexidine digluconate 1% aqueous by the North American Contact Dermatitis Group, 2015-2020. Of 14,731 patients tested to chlorhexidine digluconate, 107 (0.7%) had an allergic reaction; of these, 56 (52.3%) reactions were currently clinically relevant. Most (59%) reactions were mild (+), followed by strong (++, 18.7%) and very strong (+++, 6.5%). Common primary dermatitis anatomic sites in chlorhexidine-positive patients were hands (26.4%), face (24.5%), and scattered/generalized distribution (17.9%). Compared with negative patients, chlorhexidine-positive patients were significantly more likely to have dermatitis involving the trunk (11.3% vs 5.1%;  = 0.0036). The most commonly identified source category was skin/health care products (n = 41, 38.3%). Only 11 (10.3%) chlorhexidine reactions were occupationally related; of these, 81.8% were in health care workers. Chlorhexidine digluconate allergy is uncommon, but often clinically relevant. Involvement of the hands, face, and scattered generalized patterns was frequent. Occupationally related reactions were found predominantly in health care workers.