Food Allergy: Elimination Diet in Milk Allergy

If the patient history indicates a non-IgE-mediated food allergy, or if IgE tests are inconclusive, then the dietary method is the most reliable way of diagnosing food allergy.
The diagnosis is then made by the Elimination-Challenge Test. This should demonstrate the relief of symptoms on the removal of milk from the diet and the recurrence of symptoms when re-introduced during the challenge phase.

The dietary method consists of an elimination (or exclusion) phase and a challenge phase.

In the elimination phase the clinician attempts to remove the harmful food antigen and assesses whether patient’s symptoms improve. This procedure requires the exclusion of the suspect foods, and the maintenance of a diet free from all forms of the offending food, in the absence of secondary infections.

The amelioration of symptoms during dietary elimination of suspected foods provides presumptive evidence of a relation between these foods and the allergy.

Elimination diet in young bottle-fed infants

Elimination diets can take several forms. In young bottle-fed infants with possible cow milk allergy, a validated hypoallergenic formula should be used, either:

1. A formula based on extensively hydrolysed cows’ milk protein (whereby the intact protein is broken down into smaller fragments).
2. An Amino Acid-based Formula (AAF).

However it is important to note that where a severe allergy is suspected only the AAF is appropriate as it is considered non-allergenic for all allergic infants.
The other formulas could give false negative results. Whichever choice is given, it should be done so under close medical supervision.

Elimination diet during breastfeeding

Breastfeeding provides many benefits to babies (link to appropriate section) and should therefore be actively encouraged. Occasionally, breastfed infants will suffer allergic reactions to antigens in the mother’s diet. Antigens appear in small quantities in breast milk and for most infants they do not represent a problem. However, very sensitive infants can react to these traces.
To prevent food antigens from the maternal diet passing to the infant via the breast milk the mothers diet must be restricted.
The elimination diet of the mother indirectly affects the nutritional status of the infant, and thus the mother should be given support in how to adapt her diet accordingly. However if control of allergic symptoms and normal growth cannot be achieved because of the many antigens present in the breast milk, prolonged breastfeeding cannot be recommended and infants often have to be placed on Amino Acid-based Formulas.

Elimination diet after weaning

In older infants and children, solid foods play an increasingly important role in the diet and food elimination can be achieved in several ways.

When there is a very clear history linking a specific food or foods to symptoms, a food specific elimination diet, in which the relevant foods are avoided, may be most appropriate.
In other children, where the clinical history may be less clear and many foods are suspected, a few foods or oligoantigenic diet (where the diet is limited to foods unlikely to cause allergic reactions) may be more appropriate.
Amino acid-based formulas can be used for more extreme elimination and can play a useful support role in patients who find it difficult to meet their calorie requirements when on a few foods diet.

The length of time the patient needs to stay on the exclusion diet depends on the type of allergic disorder. This is generally 1 week for IgE-mediated disorders, 1 to 2 weeks for atopic dermatitis, 24 to 48 hours for milk-induced enterocolitis and 6 to 8 weeks for milk-induced eosinophilic esophagitis.
Once symptoms have resolved food challenges should be undertaken.

If symptoms do not improve following the exclusion diet, food allergy can be ruled out; if symptoms improve then the investigator should proceed with carefully controlled food challenges.

Elimination diets can be difficult, expensive and restrictive (we recommend reading "How to Read Food Labels"). A qualified dietitian is required to supervise and ensure the diet is nutritionally adequate.