Food allergy and Eczema

Food allergy does not directly cause eczema, it can aggravate it in some children. The most common causes are cow's milk, soy, egg, nuts, seeds, wheat and seafood allergies although sometimes other foods are involved. Fortunately, most food allergies that aggravate eczema will disappear within the first few years of life. Food allergy only occasionally aggravates eczema in adults.

The majority of children with food allergy will get intensely itchy with large hives within an hour or less of eating the offending food. Sometimes infants will have more subtle symptoms, such as irritability or a slightly worse rash after a feed. Occasionally, infants will even react to small amounts of food present in their mother's breast milk. If the mother avoids the food in her diet, the baby's eczema may improve.

Identification of the offending food (or foods) with skin prick tests or blood allergen specific IgE (RAST) allergy tests can help to identify the food/s in many cases. However, since not all positive skin tests and positive RAST tests are clinically relevant, the test results need to be assessed by a medical specialist (Allergist/Clinical Immunologist).

The final answer is often provided by a temporary elimination diet of the offending foods, usually under the supervision a medical specialist (Allergist/Clinical Immunologist), and often in association with an accredited practising dietitian, with specialised knowledge in food allergies. If the skin improves, foods are introduced one at a time (food challenges) to see whether the eczema flares up. If there is no improvement in two weeks on the elimination diet, it means that food is unlikely to be a problem.

Less commonly, reactions can be delayed over several days. Allergy testing is less reliable in this situation. Eliminating wheat and milk from the diet is inappropriate for the majority of children and long term unsupervised (and often unnecessary) dietary restriction can lead to malnutrition. It is important that elimination and challenge with foods is only conducted under medical supervision.