Non-imunoglobulin E (IgE)-mediated conditions include combined IgE and cell-mediated conditions such as atopic dermatitis and
eosinophilic oesophagitis, and pure T-cell-mediated conditions such as food protein-induced enterocolitis syndrome, allergic proctocolitis
and enteropathy syndromes.
Diagnosing mixed or non-IgE-mediated allergy is challenging. A clear cause-effect relationship between exposure to the suspected food
and symptoms is not always possible, as symptoms develop over time and are more chronic in nature. Skin-prick tests and specific IgE to
the allergen are usually negative. An elimination diet may be necessary to diagnose non-IgE-mediated type food allergy. The suspected
allergen should be excluded from the diet for 2 - 6 weeks under dietetic guidance to assess for improvement of symptoms. After symptom
improvement, a rechallenge is necessary to definitively prove causal relation.