Dirt, worms and atopic dermatitis

The past three decades have witnessed a marked rise in the prevalence of atopic diseases in industrialized countries and urban centres in less developed regions. This has led to an intense search for aetiological factors that may explain such a pattern. Epidemiological and immunological data suggest the eradication of nonparasitic and endoparasitic infections as possible aetiological elements. This has been formulated as the 'hygiene hypothesis', linking a reduced frequency of childhood infections with allergy. So far, most work in this area has focused on asthma. The potential relationship between endoparasites and atopic dermatitis has received much less attention. This paper reviews the scientific literature on the links between atopic dermatitis and endoparasites. At present, there is no clear evidence for a direct relationship between the two. This may be due to the overall small number of studies and insufficient methodological rigour in the existing body of research.