Background
There has been an increase in the incidence of true allergic disorders and in the public perception that allergies can explain a variety of symptoms. In reality, true allergies manifest in a relatively narrowly defined spectrum of clinical signs and symptoms.
The clinical immunology and allergy consultant and specialist registrar staff are available to discuss patients by telephone.
These referral guidelines aim to assist care providers in the diagnosis and management of allergic disorders and highlight those situations in which referral or a specialist opinion is recommended.
Useful information for allergy
IgE testing
The Royal College of Pathologists have published best practice guidelines for laboratory allergy tests in primary care: G194-BPR-Use-of-laboratory-allergy-testing-in-primary-care.pdf
These guidelines should be consulted where appropriate.
IgE testing (often known as RASTs tests) are only indicated for type 1 hypersensitivity. i.e. histamine mediated. Type 1 hypersensitivity reactions to aeroallergens which are inhaled cause symptoms of sneezing, nasal congestion, wheeze, rhinorrhoea, and allergic rhinoconjunctivitis.
Aeroallergen sensitisation will not cause symptoms of urticaria and anaphylaxis. However, type 1 hypersensitivity to food allergens (e.g. peanut), can cause symptoms of urticaria, life threatening angioedema, hypotension and fulminant anaphylaxis.
RAST tests are not indicated for any other reason, they are of no value in the management of adult eczema or food intolerances. Testing in these populations may lead to clinically irrelevant positive tests and subsequent patient anxiety and dietary restriction. Ultimately, they can be harmful when inappropriately requested.
We do not encourage use of commercial kits and IgG testing which are often available through non-NHS private providers e.g. York test
Skin prick testing versus patch testing
Skin prick tests are used to assess type I hypersensitivity. Patch tests are used to determine delayed hypersensitivity usually in the context of contact dermatitis. We do not provide a patch test service, where there is a suspicion of contact dermatitis, the referral should be made to a local patch testing service (dermatology).