Food Challenges Exceptional healthcare, personally delivered
Introduction You have been referred to the Immunology department to explore your food allergies. This leaflet provides information on allergies and tests after a severe reaction to food. What is a food allergy? Food allergies affect approximately 1 in 50 adults at some stage of their life. They are one of the most common causes of serious allergic reactions, known as anaphylaxis (sudden collapse). The most common foods to be involved are peanuts, tree nuts, fish and shellfish. What happens after I have had a severe reaction? You have been referred to a centre specialising in allergy, where you may have a blood and / or a skin prick test. This will help to identify which food caused your reaction. In some cases (after a negative test) a food challenge may be offered. What can I do to prevent a further reaction? In the case of confirmed allergy, the food should be avoided. Over time the allergy may lessen. What is a food challenge? A food challenge is the best way to assess how you will react to a particular food. The challenge is performed in a hospital in order that you can be closely monitored. The challenge will only be performed if you are feeling well. If you have an infection, uncontrolled asthma, cardiac problems or are taking medication that may interfere with the challenge (e.g. beta-blockers) please inform the person performing the challenge. If you are taking anti-histamines you will be asked to stop taking them 5-7 days before your challenge is performed. Please contact us on receipt of your appointment to confirm or rebook as there are limited appointment times available for challenges. 2 Food challenges
How is it done? An appointment will be made for you to attend the allergy clinic. You will be asked to bring with you the food that may be causing your reaction. If you are being challenged with more than one food, remember to bring the foods in separate containers to prevent cross-contamination. Your challenge will continue as follows: n Increasing doses of the food are given over time, with close observation for reactions. Observations will include pulse, blood pressure and peak flow (a measure of lung capacity). n The exact duration and number of stages will depend on previous reactions and symptoms during your test. n The amount of food required will vary but assume about 100grams. n After the final dose you will be observed for 2 hours before you can be discharged. What kind of reaction may I have? You will be closely monitored for three types of reaction n Acute local lip/facial swelling, itchy rash, hives (small raised lumps). n Anaphylaxis, acute onset of drowsiness, wheezing, and collapse. n Delayed abdominal pain, vomiting and diarrhoea; this kind of reaction may occur the following day. It may be distressing but is not dangerous. You will need to contact the immunology department to let them know that this has occurred. If you had no reaction following the challenge it is safe to start eating that food. Food challenges 3
What happens if I reacted to the food? n The food challenge will be discontinued and appropriate treatment given, if necessary. n Ward admission may be required if a severe reaction occurs, in order to monitor you closely for any further deterioration. You will be advised to avoid this food completely or any products containing the food that you are allergic to. 4 Food challenges
References and further information Hourihane, J et al (1996) Peanut Allergy in Relation to Heredity, Maternal Diet and Other Atopic Disorders. British Medical Journal, 313, 518-521. McAlister, L (1997) Peanut Allergy, Information for Dieticians. Information Leaflet. London: British Dietetic Association. North Bristol NHS Trust (2005) Food Challenges. Patient Information Leaflet No NBT002306. Institute of Child Health Great Ormond Street Hospital for Sick Children Information Fact Sheet on Peanut Allergy. Website available: www.ich.ucl.ac.uk/factsheets Allergy UK Planwell House LEFA Business Park Edgington Way Sidcup Kent DA14 5BH Telephone 01322 619898 Website: www.allergyuk.org British Dietetic Association 5th Floor, Charles House 148/9 Great Charles Street Queensway Birmingham B3 3HT Telephone 0121 200 8080 Website: www.bda.uk.com Food challenges 5
NHS Constitution. Information on your rights and responsibilities. Available at www.nhs.uk/aboutnhs/constitution Food challenges 7
www.nbt.nhs.uk If you or the individual you are caring for need support reading this leaflet please ask a member of staff for advice. North Bristol NHS Trust. This edition published May 2014. Review due May 2016. NBT002306