Topics in Allergy
Oral Itch Syndrome From Food Allergy
Some people notice immediate itching in and around the mouth after eating certain foods, especially fresh fruits and vegetables. This occurs because of a cross reaction between antigens (protein molecules) in food with antigens in pollens and typically involves fresh fruits and vegetables. The foods are often tolerated if cooked, canned or otherwise processed because processing changes the antigens in the food and they are no longer recognized by the patient’s immune system. These reactions almost never progress to anaphylaxis (severe life threatening reactions) but may cause annoying immediate itching in the mouth and face and sometimes trigger nasal symptoms or asthma.
People with weed pollen allergies often react to melons, bananas, and avacados and people with tree pollen allergies (especially birch) often react to peaches, cherries, pears, apples, and plums. Antihistamines may help prevent the itching. Allergy shots to the cross reacting pollens will sometimes reduce or eliminate the oral itch syndrome from foods. Often, however, the only good solution is to avoid the fresh fruits or vegetables that cause the reaction.
A second type of reaction occurs in some people who do not have pollen allergies but do react with oral itching when eating fruit. This reaction is not due to a cross reaction of antigen in the food with pollen antigens but is a result of a persons immune system making antibody specifically against the antigen in the food. This type of reaction is somewhat more likely to result in an anaphylactic reaction than the type where food allergens cross react with pollen allergens. Some people choose to carry an EpiPen (injectable adrenalin) in case a severe reaction occurs.