Oral food challenges are tests that use suspected food allergens. 

What to expect

  • Traces of the food are initially rubbed onto your lower lip.
  • Then traces are placed inside the lip.
  • Then increasing doses of the food are given to you every 10–15 minutes until, finally, you are able to consume a substantial amount of the food without an allergic reaction.  

The foods that we most commonly test are peanuts, tree nuts and shellfish. The main symptom that you will experience if you are sensitive to the allergen during the food challenge, is itching in the mouth and throat. You may also experience wheezing and respiratory difficulties, and sometimes patients can experience more severe symptoms, such as swelling and hives. 

It is essential that the tests take place under close medical supervision because sometimes patients with negative skin prick and blood tests to a food can have an unexpected positive reaction during the challenge.

Anaphylaxis is a serious allergic reaction that can be life-threatening or fatal.

People with hay fever (rhinitis) have inflamed lining in their nose, which causes it to be blocked, running and itchy, as well as causing sneezing.

Urticaria is a condition which involves the development of itchy wheals (hives) on the skin.

Around 5–10% of people who have a problem with a drug are suffering from a drug allergy, possibly one prescribed by their GP or as part of an investigation in hospital. 

Between 1-10% of adults and children in the UK have a food allergy.

The Trust offers a wide range of allergy services for adults of all ages. This includes specialist services for patients with difficult to manage allergies.

Allergy team contact details


Fulham wing/South block, Fulham Road

Tel:  +44 (0)20 7351 8892
Fax: +44 (0)20 7351 8949