Food allergy and food intolerance are commonly confused because the symptoms of food intolerance occasionally resemble the symptoms of food allergy. However there are important differences between the two.
A food allergy is an overreaction of the body’s immune system to an ordinarily harmless component within a food. The food is perceived as “foreign” and therefore threatening, so the immune system produces allergen-specific immunoglobulin E (IgE) antibodies to protect the body. In response to an “infestation” the IgE antibodies bind to food allergens; triggering the release of histamine from mast cells and an immediate hypersensitivity reaction.
A food intolerance is a chemical reaction rather than an IgE-mediated immune response. Chemicals within food cause reactions by irritating nerve endings throughout the body. Unlike a food allergy though, a food intolerance cannot illicit a severe allergic reaction, or anaphylaxis.
It can be difficult to tell the difference between the symptoms of food allergy and food intolerance. In general, symptoms caused by a food allergy develop very quickly after consuming the offending food. Symptoms of food intolerance can be immediate, but usually develop after 12-24 hours. Furthermore, unlike with food allergy reactions, food intolerance reactions are usually related to the amount of food consumed. An individual with food intolerance may be able to eat small amounts of the offending food without experiencing symptoms.
Common symptoms of food allergy include:
- Itching, burning or swelling around the mouth
- Runny nose, sneezing, nasal stuffiness
- Watery, itchy eyes
- Breathing difficulties, including wheezing, coughing and asthma
- Abdominal cramps, vomiting and diarrhoea
- Eczema, hives
- Anaphylactic shock
- Swelling of the tongue and throat
- Breathing difficulties
- Wheezing, persistent coughing and asthma
- Dizziness or loss of consciousness
Common symptoms of food intolerance include:
- Mouth ulcers
- Asthma-like symptoms
- Sinus problems
- Headache, migraine
- Nausea, abdominal pains/bloating and bowel irritability
- Burning sensations across the skin
- Tightness across the face and chest
- Chronic fatigue and general feeling of being run down
- Irritability and restlessness (more common in children)
At Allergy First Gold Coast clinic we conduct skin prick testing for food allergies.