Food allergy and food intolerance are commonly confused, as symptoms of
food intolerance occasionally resemble those of food allergy. However, food
intolerance does not involve the immune system and does not cause severe
allergic reactions (known as anaphylaxis). Food intolerance also does not
show on allergy testing.
Food intolerance can be a difficult concept to understand and is poorly
understood by doctors as well. Sometimes, substances within foods can
increase the frequency and severity of migraine headaches, rashes (such as
hives) or the stomach upset of irritable bowel.
Professional diagnosis and confirmation of allergens is important. In
Australia, about one in 10 infants, one in 20 children up to five years of age,
and two in 100 adults have food allergies.