Allergy in the mouth, otherwise known as oral allergy syndrome, is the most common type of food allergy. According to the American Academy of Family Physicians, or AAFP, it is present in up to 10 percent of patients with allergic rhinitis or asthma that is related to grass, weed, or tree pollen. Patients with this type of allergy develop itching and tingling of the mouth in response to the ingestion of certain foods. This reaction develops because the person is allergic to the proteins in a type of pollen that is similar to the proteins in the food that he has ingested. While symptoms are bothersome, they typically occur only with ingestion of raw food. There are multiple types of pollen and foods that can cause this reaction.
Birch Pollen
Birch pollen is the most common pollen associated with oral allergy syndrome. This is a tree pollen and, typically, causes symptoms of allergic rhinitis, such as itchy eyes and runny nose, when trees bloom in the spring. Patients with an allergy to birch pollen may develop an oral allergy syndrome to apples, carrots, celery, hazelnuts, peaches, pears and potatoes because the proteins in these foods are similar to the protein in birch pollen.
Ragweed Pollen
Ragweed pollen is predominant in late summer and fall and is a common cause of allergic rhinitis and asthma. Patients with allergies to ragweed pollen are most likely to have allergies in the mouth to bananas, melons and tomatoes. This reaction will most commonly occur within a few minutes of placing the food into the mouth. Melons can include cantaloupe, honeydew and watermelon.
Grasses
Grass allergies tend to be worst in the summer, but they are often a problem whenever grass is growing rapidly. In some areas of the country, this is from the early spring through the late fall. The allergenic protein in grass is similar to the protein in kiwis and tomatoes. For this reason, a patient with an allergic reaction to grass may develop oral allergy syndrome to these fruits.
Mugwort Pollen
Allergies to mugwort pollen is more common in England, but it can be a problem in the United States as well. The allergenic protein in mugwort pollen is similar to the protein in apples, watermelon, celery, carrots, and in some spices, such as fennel and caraway. Patients with allergy to mugwort pollen may develop oral allergy syndrome to these fruits and vegetables. Cooking the foods prior to eating often changes the protein enough so that the mouth allergy does not occur.
