A food allergy is an exaggerated immune system response to a food protein and the body triggers an allergic reaction. Symptoms can include hives, itching, swelling, vomiting, diarrhoea and nausea. In some cases, it can cause potentially life-threatening symptoms, called anaphylaxis, either by breathing difficulties and/or a sudden drop in blood pressure.
Sometimes food allergy may be less obvious and can be characterised by infantile colic, reflux of stomach contents, eczema, chronic diarrhoea, and failure to thrive. Recent studies have found that up to 40-50 per cent of eczema cases in young children are triggered by food allergy.
Eight foods cause 90 per cent of allergies: milk, egg, peanuts, tree nuts, fish, shell fish, wheat and soy. However, any food can cause an allergic reaction.
A food intolerance is an adverse reaction to a food that does not involve the immune system. Reactions can be immediate or delayed up to 20 hours after a food is eaten.
Symptoms of intolerance are sometimes vague and can include a combination of the following: gastrointestinal problems such as bloating and wind, diarrhoea, nausea and indigestion, aggravation of eczema or asthma. Food intolerances can sometimes mimic symptoms of other medical conditions - it is important to get checked out by a doctor to eliminate other problems first.