Eczema and allergy: the chicken or the egg?

Abstract

Eczema is a common problem in general paediatric consultations. Treatment of eczema is essential because irritated and inflamed skin stimulates the onset of sensitisation and subsequent allergy, particularly food allergy. Treatment is currently based on non-aggressive corporal hygiene, daily application of emollients and early treatment of flares with topical corticosteroids.

In severe cases, an allergic aetiology is often suspected. Early-onset eczema before the age of 6 months and/or steroid-dependent eczema are more likely to be allergic in origin. In these cases, cow's milk is the main culprit, either in artificial milk or via breast milk. Eviction would help to reduce the intensity of the disease. In the older children, an allergic trigger is found in only 10% of cases.

However, a very large number of patients have asymptomatic sensitisation (positive skin prick test and/or positive specific IgE) which  should not be confused with allergy. In fact, if eliminating the food does not improve the cutaneous symptoms, it is not only useless but may even promote a breach of tolerance and increase the risk of becoming truly allergic to that food.