BACKGROUND: Recently, clonidine has been increasingly utilized for the treatment of tic disorders in children rather than for hypertension in adults. The transdermal patch is a common route of administration. Allergic contact dermatitis caused by clonidine transdermal patch was reported in adults with hypertension but never in children with tic disorder. OBJECTIVE: We report on the first pediatric case developed allergic contact dermatitis within one to two weeks after using clonidine transdermal patch. METHODS: Patch test with clonidine and Chinese baseline series including adhesive components (ethyl acrylate, methyl methacrylate, and 2-hydroxyethyl methacrylate) from the adhesive layer of the transdermal patch were performed. RESULTS: We report the first pediatric case with allergic contact dermatitis due to clonidine transdermal patch confirmed by patch test. She presented with pruritic erythema, blistering, and rupture at the patch site, matching its size and shape. Patch test with clonidine hydrochloride elicited positive reactions (++ to +++), while tests for specific components from the adhesive layer, including ethyl acrylate, methyl methacrylate, and 2-hydroxyethyl methacrylate, were negative, thereby identifying clonidine as the primary allergen. CONCLUSIONS: This case highlights that although clonidine itself has weak sensitizing potential, the transdermal therapeutic system may increase the risk of clonidine-induced sensitization and make it become a potential trigger for allergic contact dermatitis in clonidine transdermal patch users.
Xu et al. (Mon,) studied this question.