Diphenhydramine allergic contact dermatitis

Skin Allergic contact dermatitis has been attributed to diphenhydramine [13 ]. 

The authors concluded that the patient had had allergic contact dermatitis due to both metronidazole and diphenhydramine. 

Femandez-Jorge B, Goday J, Buja N, Fer-nandez-Torres R, Rodriguez-Lojo R, Fonseca E. Concomitant allergic contact dermatitis from diphenhydramine and metronidazole. Contact Dermatitis 2008 59 115-6. 

Individuals who have become sensitized by topically applied diphenhydramine can acquire a systemic eczematous contact dermatitis when diphenhydramine or any of the other ethanolamines listed in Table 5 is ingested or injected (Fisher 1973 It is not generally realized that dimenhydrinate (Dramamine) is an ethanol-amine (the chlorotheophylline salt of the antihistaminic agent diphenhydramine). Dimenhydrinate contains between 53% and 56% diphenhydramine and therefore should not be administered to any individual with allergic hypersensitivity to the ethanolamine group of antihistamines. 

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