IgE mediated food allergy – Life threatening
IgE-mediated food allergy manifests by a small range of symptoms, nearly always including urticaria and angioedema on ingestion of the potential allergen.
Common allergens include nuts, seafood, and eggs.
Where there is a suspicion of a food allergy a specific IgE to the food should be performed before referral.
IgE mediated food allergy – Oral allergy syndrome
Oral allergy syndrome is an IgE mediated food reaction. It rarely leads to life threatening reactions and an adrenaline autoinjector is rarely warranted. It is characterised by immediate onset mouth, palatal and throat itching on ingestion of raw fruits, vegetables, and nuts. While occasionally there may be mild throat and lip swelling, life threatening anaphylaxis is rare as the allergen is quickly digested to a non-allergic form by gastric secretions. Similarly, cooking the allergen will render it inactive and hence patients will tolerate roasted nuts and cooked fruit, but not the raw form.
Oral allergy syndrome
Oral allergy syndrome is a clinical diagnosis, where the symptoms are convincing, and mild the patients do not need to be referred. The following website provides useful patient information:
Oral Allergy Syndrome (Pollen Food Syndrome) | Allergy UK | National CharityCases where the history is less clear should be referred.
Food intolerance
Symptoms of brain fog, headache, bloating, constipation, diarrhoea and abdominal discomfort related to food are symptoms of an intolerance not allergy. A referral to an allergist for further assessment is unlikely to identify any obvious triggers. We do not accept referrals for food intolerance, there are no validated blood or skin tests for food intolerance. Non-NHS tests such as hair sample testing, IgG testing (York Test) are not recommended.
IgE RAST tests are not indicated for food intolerance.
Intolerance
Patients should be directed to the following website:
Allergy vs Intolerance | Allergy UK | National CharityAdverse reactions to alcohol
Flushing and hives in response to alcohol are not IgE mediated There is not a significant risk of anaphylaxis. The effects are usually dose dependent. Apart from avoiding culprit drinks no further investigation or intervention ids required.
Eosinophilic Oesophagitis (EoE)
Understanding of EoE has changed over the last 5 years, the basis of the disease is not IgE mediated. As we do not add anything to the care of these patients, we no longer accept them.
Food and eczema
The role between food and eczema is complex, however there is no role for IgE testing in eczema without food allergy symptoms. Atopic individuals will often have a raised IgE and positive IgE tests which are clinically irrelevant.
IgE tests to solely investigate eczema is therefore in appropriate and may lead to undue patient anxiety and food avoidance.
Urgent referral criteria
Multiple suspected food allergy leading to significant dietary restriction
Routine referral criteria
History of suspected IgE mediated food allergy
Not to refer
- Food intolerances
- Adverse reactions to alcohol
- Eosinophilic oesophagitis
- Eczema