Those who are allergic to fresh tomatoes but find they are able to eat them cooked without any adverse effects may have oral allergy syndrome, also referred to as OAS. According to the National Institute of Allergy and Infectious Diseases, sufferers of seasonal allergies such as hay fever are more likely to develop OAS. Heat changes the proteins in fruit and vegetables associated with oral allergy syndrome, and the body no longer recognizes the allergen, allowing the item to be eaten cooked or as an ingredient in commercially processed products.
Causes
A cross-reactivity between grass pollen and tomatoes often is responsible for allergic reactions to fresh tomatoes, according to The Children’s Hospital of Philadelphia. Those with allergies to grass also may be sensitive to melon, oranges and peaches in addition to raw tomatoes. A general food allergy to tomatoes is a more serious condition, and those affected may experience an all-over body reaction or anaphylaxis.
Symptoms
Tomato-induced allergy symptoms associated with OAS are short-lived, and researchers at the Medical College of Wisconsin found that participants in a study did not experience serious or long-lasting effects when exposed to tomato allergens. Oral allergy symptoms are limited to the mouth and throat and typically include itching and irritation to the soft tissue. Swelling and blisters on the lips are uncomfortable but subside within an hour or so. Difficulty in breathing or swelling elsewhere could be a sign of anaphylaxis from a general food allergy. Seek immediate medical attention if a whole-body reaction is suspected.
Treatment
Localized reactions to fresh tomatoes rarely require treatment, and symptoms disappear of their own accord. Rinsing the mouth with water removes any remaining tomato residue and cools the affected area. Dr. Anthony Ham Pong, writing on the Calgary Allergy Network website, suggests that those who have previously experienced a serious adverse reaction to tomatoes consider carrying an epinephrine injection to administer emergency treatment. Seek advice from an allergist
Precautions
Avoid cross-contamination from raw tomatoes when eating out. Chopping boards and knives used to prepare tomatoes often are used in the preparation of other salad ingredients in a restaurant’s kitchen. Ask the server if the chef can prepare your meal in a tomato-free area. Seek advice from an allergist about acquiring a medical alert bracelet for your child if he is allergic to fresh tomatoes. Information contained within the bracelet states the child’s allergy and treatment advice in the event of an allergic reaction.
References
- National Institute of Allergy and Infectious Diseases: Oral Allergy Syndrome
- The Children's Hospital of Philadelphia: Allergy Clinical Services: Oral Allergy Syndrome
- National Center for Biotechnology Information; Severe Tomato Allergy (Lycopersicon Esculentum); M.C. Zacharisen, et al.; 1996
- Allergist: Oral Allergy Syndrome
- Ohio State College of Medicine, Division of Sinus and Allergy: Oral-Allergy Syndrome
- Calgary Allergy Network; AAIA Articles; Oral Allergy Syndrome; Anthony Ham Pong, M.B., B.S.
Member Comments