Changing patterns of contact allergy in chronic inflammatory ear disease.

Chronic inflammatory ear disease comprises a wide range of conditions. Although contact allergy to topical medicaments is common in such conditions, the causes of these reactions have not been examined in a large series for over a decade. Our aim was to investigate the major sensitizers recorded in 179 patients over the last 17 years. Medicament contact allergic dermatitis was diagnosed in 45 patients (25%), of whom 34 (76%) demonstrated a relevant allergy to neomycin, 28 (62%) to framycetin, 11 (31%) to gentamicin, 8 (18%) to quinoline mix and 5 (11%) to caine mix. Of all neomycin-allergic patients, 28 (76%) were also allergic to framycetin and 12 (43%) to gentamicin. Comparing the first 60 patients (1985-94) to the most recent 60 (1998-2002) identified a significant recent reduction in the number of patients allergic to neomycin (P = 0.002) and framycetin (P = 0.050), with a non-significant reduction in the total number diagnosed as medicament-allergic (P = 0.066). We have therefore demonstrated a high frequency of medicament contact allergy in chronic inflammatory ear disease, supporting the routine use of patch testing in these patients. We have also shown a significant recent reduction in the number of such patients with allergy to neomycin and framycetin.