What is a Food Allergy?
A food allergy is an adverse immune response to a particular food, with the body mistaking it as harmful. Although any food can potentially trigger an allergy, foods that commonly cause an allergic reaction are milk, soya, eggs, peanuts, wheat, fish and shellfish.
It is important not to confuse a food allergy with food intolerance, which does not involve the immune system, has different symptoms and is never immediately life threatening.
What are the Symptoms of a Food Allergy?
Symptoms usually develop within a few minutes to an hour after exposure to the food and commonly include:
· Tingling or burning sensation around the lips and mouth
· Itches and rashes
· Swelling of lips or face
· Wheezing or uncontrollable sneezing
· Nausea and vomiting
· Diarrhoea
Severe anaphylactic reactions can also result in a rapid heartbeat (tachycardia), a drop in blood pressure, severe breathing difficulties, and unconsciousness. Anaphylaxis is a medical emergency and without treatment can result in coma or death.
What Causes a Food Allergy?
All food allergies are caused by an inappropriate immune response to the particular food. The immune system produces specialised cells called antibodies, which protect the body against possible infection and harm. However in food allergies, a type of antibody called IgE, mistakes specific proteins found within the food as a threat to the body. It responds by triggering the release of chemicals which cause the symptoms of food allergies. An important chemical released is histamine, which can cause swelling, itching, and inflammation.
Risk factors
- Family history
- Other allergic conditions e.g. asthma
- Change in western diets e.g. decreased consumption of antioxidants and Vitamin D
- Hygiene hypothesis – children growing up in increasingly ‘germ-free’ environments, thereby not fully developing their immune systems
How is a Food Allergy Treated?
Identity of the food that causes the reaction and its avoidance is the best form of prevention. You will need to not only avoid eating or drink the food, but also avoid inhaling, touching, and any cross-contamination with it. You should check food labels for ingredients or for any allergy warnings on the packaging e.g. ‘may contain traces of peanut’.
You will be given two forms of medication for potential emergencies. These are antihistamines, which block the actions of the chemical histamine, and adrenaline, which manages symptoms of anaphylaxis. If you believe you are experiencing an anaphylactic reaction, you should immediately inject yourself in the thigh or upper arm before calling for an ambulance. Those who know that they suffer severe reactions should carry an emergency Epipen with them at all times.
Dr. A. Bose © Allcures.com November 2011