Prevalence and associated factors of atopic dermatitis symptoms in rural and urban Ethiopia

Background Allergic diseases, including atopic dermatitis (AD), are increasingly becoming a clinical problem in developing countries. Objective We investigated the prevalence of AD symptoms and the effects of potential environmental aetiologies in rural and urban areas of Jimma in southwestern Ethiopia. Methods Information on allergic disease symptoms and lifestyle factors was gathered in an interviewer-led cross-sectional questionnaire-based population survey of 9844 urban and 3032 rural participants of all ages. A one-in-four subsample underwent skin prick testing for hypersensitivity to Dermatophagoides pteronyssinus, mixed threshings, and aspergillus. Results Around 95% of those eligible took part in the survey. Lifetime cumulative prevalence of AD symptoms was generally low with an overall prevalence of 1.2%, but was higher in the urban (1.5%) than in the rural area (0.3%; odds ratio (OR)=4.45 [95% CI 2.34-8.47]). AD symptoms were strongly associated with wheeze (adjusted OR=22.03 [15.45-31.42]) and rhinitis symptoms (61.94 [42.66-89.95]). Of several environmental exposures assessed, residence in a house made of brick (rather than mud) walls with wooden (rather than clay) floor, exposure to cigarette smoke as a child, having lived outside of Jimma in the past, and being of the Tigrean ethnic group were associated with an increased risk of AD symptoms. Conclusion Although the overall prevalence of AD symptoms was low in this Ethiopian population, a marked urban-rural gradient was evident. Lifestyle factors linked to urbanization were associated with an increased risk of AD symptoms.