Ear contact dermatitis: Epidemiology and main contact allergens in Dakar, Senegal

Background: Ear eczema is a frequent pruritic inflammatory dermatosis in dermato-allergology, with an estimated prevalence of 7–19% worldwide. It has multiple causes, with a predominance of allergic contact eczema. The aim of this study was to determine the epidemiological characteristics of ear eczema and to identify the main contact allergens responsible. Patients and Methods: This was a descriptive, cross-sectional, multicenter study conducted over a seven-month period at the Dermatology Departments of Aristide le Dantec Hospital, the Social Institute and the Medical Institute of Université Cheikh Anta Diop, and the Cervico-Facial Department of Fann Hospital. We included all patients with ear eczema who had undergone allergological tests and a nickel spot test if metal allergy was suspected. Data entry and analysis were performed using SPSS, version 18. Results: We recorded 46 cases of ear eczema, with a hospital frequency of 0.46%. The mean age was 22 years, with extremes of 5 months and 85 years. The sex ratio was 0.84 (25 women, 21 men). Personal atopy was present in 80% of the cases. Ear eczema lesions were chronic in 28 cases and acute in 18 cases. The outer ear was the site of lesions in 30 cases (65%), with both ears and symmetrical lesions. Ear involvement was isolated in 17% of the cases, and associated with face eczema in 10%, the hands in 13%, and the scalp in 6%. Lesions of the external auditory canal were noted in 4% of the cases. The standard European battery using the patch test was positive in all patients. The main contact allergens were noted for nickel in 42%, cobalt in 35%, PPD in 28%, and thiuram mix in 28%. Patch tests were relevant and concordant in 85% of the cases. The positivity of the nickel test was more relevant for six cases of contact allergy to metals. Conclusion: Ear eczema remains a common dermatosis in dermato-allergological, with a predominance of metal and cosmetic allergens in Dakar. Improving cosmetovigilance, especially by regulating the concentration of nickel in cosmetic products and costume jewelry, could help to reduce the incidence of metal-allergy contact dermatitis.