Food-provoked eczema: A hypothesis on the possible role of systemic contact allergy to haptens present in both cosmetics and foods

Abstract

Patients with eczema frequently associate relapses of their disease with ingestion of particular foods, however, the actual causation by food allergens can be confirmed only in a minority of them. In the present paper, a hypothesis is proposed on the possible causal link between eczema and food in cases not explainable by type I allergy to “classical” food allergens like egg, milk or peanut protein. It is proposed that eczema in such cases may be due to delayed-type allergy to haptens present in food – either natural components, contaminants, or food additives. A wide range of haptens are used in the production of both food and cosmetics. It is proposed that initial sensitization of the skin to a hapten may follow external exposure (e.g. from skin care products), while relapses in the course of eczema may be due to subsequent oral exposures to the same hapten from food (systemic contact dermatitis). This hypothesis also offers an explanation for cases of photoaggravated eczema by indicating on food haptens with photosensitizing properties. The proposed hypothesis is unifying recent scientific discoveries and clinical observations in the attempt at explaining cases of food-provoked eczema that could not be explained by the present mainstream views on food allergy. Nevertheless, it requires thorough verification through dedicated research aimed specifically at testing the proposed causal relationship between food-provoked eczema and haptens occurring in both cosmetics and foods. If confirmed, appropriate diagnostic methods (e.g. patch test panels with food haptens or specially devised in vitro tests) should be introduced into routine diagnosis of eczema. Furthermore, results of such studies will provide scientific evidence for possible restrictions on the use of food additives identified as potent sensitizers within the legal scheme of consumer protection policy.