Foot and ear disease--the dermatophytid reaction in otology.

Chronic otitis external (COE) is occasionally refractory to treatment and may persist for years. In such cases, a dermatophytid (id) reaction from a fungal infection in a remote location should be suspected. Immunotherapy with dermatophyte (Trichophyton, Oidiomycetes, and Epidermophyton [T.O.E.]) extracts and dust mite, based on serial endpoint titration skin test results, as well as a yeast elimination diet, is the treatment of choice. Fourteen cases of id reaction are described. The primary fungal source was not always obvious, but immunotherapy and diet led to complete resolution of the COE in 8 cases (21.4%). Some case reports illustrate presentation, treatment, and outcome.