An allergy focused clinical history (AFCH) is taken to determine whether an infant or child is likely to have a food allergy and contains the following types of questions:
- Family history of atopic conditions like asthma , eczema, hayfever in parents and siblings
- Individual history of atopy in infancy with eczema in the first 3 months being particularly relevant
- Growth and feeding history using a centile chart as a timeline to understand how feeding changes/patterns influence the development/progression of symptoms
- Current signs and symptoms, focusing on the skin, gut and respiratory systems
- Details of previous and current management of condition, including medications or changes in diet
An allergy focused dietary assessment is the next step, in which food specific questions are used to determine the type of adverse reactions occurring and which foods are implicated:
- Diet history from birth; breast or bottle feeding; weaning and adaption to family foods
- The amount of food required to produce a reaction
- Timing of reaction to suspected food to determine the likelihood IgE or non IgE reactions
- Overall exposure of the suspected food over time
- Assessment of the severity of the reactions – either mild, moderate or severe
- Consider relevance of allergy test or referral to specialist services for further clarification
Diagnostic Food Exclusion
Food allergy testing is only of value in IgE or immediate reactions to foods. Confirming (or excluding) a diagnosis of food allergy for non-IgE food allergy therefore relies on the diagnostic food exclusion. When a major food group is suspected, such as in Cow’s Milk Allergy in Infancy, the exclusion should be undertaken with the supervision of a GP, Paediatrician, Allergy Specialist or Paediatric Dietitan. This helps avoid specific nutrient deficiencies or growth faltering in infants. A diagnostic food exclusion diet for 2-4 weeks, followed by a carefully planned reintroduction is the next step. Confirmation of diagnosis cannot be made by this method unless relapse of symptoms is experienced with the reintroduction of the suspected food. This approach is suited to primary care only on the diagnosis of non-IgE delayed reactions, and not ever for the more severe and immediate IgE reactions.
When there is no doubt of the allergy or when the allergy has been confirmed, the food exclusion would continue for at least 6 months. If an infant or young child has severe or troubling ongoing symptoms, including growth faltering food reintroduction would not usually begin until the symptoms and/or growth had improved.