Contact sensitivity to miconazole with ortho-chloro cross-sensitivity to other imidazoles.

A case of allergic contact dermatitis from miconazole is reported. Patch testing with a series of azole antimycotics was positive only to miconazole, isoconazole, tioconazole and oxiconazole. Those reacting are all beta-substituted 1-phenethyl imidazoles with an ortho-chlorine substitution on the aromatic ring. For this hitherto unreported pattern of cross-sensitivity, the designation of "ortho-chloro cross-sensitivity" is proposed.