Chemical atopy

Background. Although atopic disease is associated with protein allergy, its relationship with chemicals (haptens/contact allergens and irritants) is less clearly defined. The ‘hapten–atopy’ hypothesis, whereby significant hapten and irritant exposure during times of natural T helper (Th)2 bias (pregnancy and first year of life) promotes the development of atopy and atopic disease in the resulting child, has been previously proposed. Supporting evidence includes the practice of repeated cutaneous application of haptens in generating animal models of atopic dermatitis, and the observation of a significant increase in atopic disease in children born to mothers with occupations associated with high chemical exposure during pregnancy.Objectives. To observe the relationship between personal chemical exposure and atopic disease in a particular case series.Methods. We report a case series of exacerbation of atopic dermatitis after repeated cutaneous chemical exposure.Results. Most of the patients had atopic dermatitis in young childhood that had resolved. However, after repeated chemical exposure, either occupationally as an adult or after starting to use cosmetics as a teenager, there was clear exacerbation of atopic dermatitis. Patch tests gave negative results in most cases.Conclusions. We propose that repeated exposure to chemicals in patients with an atopic background can occasionally lead to reactivation of atopic dermatitis.