Oral Allergy Syndrome

Oral allergy syndrome can be seen in patients with pollen allergy who experience mouth and throat itching, typically with fresh fruit and vegetables such as apples, melons, celery, and carrots, but also with peanuts and tree nuts such as hazelnut. Most symptoms are felt in the mouth, but there may also be gastrointestinal symptoms such as nausea, vomiting, diarrhea and abdominal pain. Occasionally patients also describe symptoms similar to pollen exposure such as itching eyes and nose, congestion and runny nose. Rarely patients develop throat swelling, hives or anaphylaxis.

Most often oral allergy syndrome begins with a pollen allergy such as birch, ragweed or grass. Most often oral allergy syndrome begins with a pollen allergy such as birch, ragweed or grass. Oral symptoms are seen among 70% of birch sensitive patients and 20% of grass sensitive patients. An allergy to particular foods may follow.

Compounds in certain foods are similar to compounds on the surface of pollen grains. Acting as a local allergen, these compounds can trigger mouth and throat itching among sensitized people. Many of these compounds are concentrated near fruit skins, so a peeled apple may cause fewer symptoms than the unpeeled fruit. Many food allergens degrade with cooking and digestion so apple sauce may cause fewer symptoms than fresh apples, cooked carrots may cause fewer symptoms than raw carrots. Those on stomach acid blocking medications may experience more gastrointestinal symptoms, as these medications impair gastric digestion.

Pollen and the related foods which may cause symptoms

  • Birch — Apple, carrot, celery, cherry, peach, apricot, pear, potato, hazelnut, peanut
  • Ragweed — Cantaloupe and other melons, banana, zucchini, mango, milk, mint, lettuce
  • Grass — Legumes (peas, beans, soybeans, all beans such as kidney, navy, garbanzo, etc.), grains, apple, carrot, celery, orange, tomato, white potato, zucchini
  • Cedar — Apple, cherry, bell peppers, kiwi, paprika, tomato
  • Mugwort — Broccoli, cantaloupe, carrot, celery, mustard, peanut, sage, rosemary

Oral allergy symptoms are seen more often during peak allergy season:

  • Spring for birch
  • Summer for grass
  • Fall for ragweed

Symptoms may become more noticeable if large or frequent amounts of a food are eaten.

The mainstays of treatment are:

  • Limit the amount and frequency of symptom-causing foods, particularly during peak allergy seasons
  • Treat the underlying allergy with sublingual immunotherapy
  • Use oral antihistamines to control symptoms temporarily