Symptoms such as itchiness after eating raw fruit indicates oral allergy syndrome, which is an abnormal reaction to a protein in certain foods. In 2007, about 3.9 percent of children under 18 years old were reported to have a food allergy, according to the U.S. Centers for Disease Control and Prevention. However, 2 percent of adults are also affected. The most common culprits causing food allergies include shellfish, nuts and milk, but other foods such as fruits can also trigger reactions.
The causes of oral allergy syndrome, also known as pollen-food allergy syndrome, are not well-known. It can cause symptoms such as itching, burning, or swelling in your lips, mouth and throat and nausea within minutes of eating the food, or up to an hour later in some cases. In some cases your ears may also itch, and in extreme cases, you may develop an anaphylactic reaction. Most children outgrow food allergies, but in some cases it can become a lifelong health problem, notes the CDC. Not all food allergies fall under the umbrella of oral allergy syndrome. Some fruits or other foods can also cause symptoms such as diarrhea or skin rashes.
Risk Factors
People with oral allergy syndrome typically have hay fever before the symptoms related to food consumption occur. Allergies to certain types of pollen can also increase your risk of developing oral allergy syndrome. For instance, being allergic to birch pollen might make you more prone to an allergy to apples, cherries, peaches, pears or plums. An allergy to ragweed can possibly make you prone to reacting to fruits such as melons, kiwi or banana. However, the pollen-associated risk can differ from person to person.
Mechanism
When you have a fruit allergy, your immune system reacts to a certain food or a substance in the food as if it was harmful. As a result, your immune system starts to pump out antibodies called immunoglobulin E, or IgE, to counteract this perceived allergen. When you eat the food again, the immunoglobulin E antibodies detect it and trigger your immune system to release histamines and other chemicals, which cause allergic symptoms such as itchiness, nausea and anaphylactic shock.
Diagnosis
Only a diagnosis through an immunologist can properly determine if your reaction to eating fruit is oral allergy syndrome. Your physician should use a variety of tests to diagnose your condition, according to the Guidelines for the Diagnosis and Management of Food Allergy in the United States published in the "Journal of Allergy and Clinical Immunology" in December 2010. These tests include blood tests, a skin prick test, oral food challenges, which involves getting you to eat a small amount of the suspected fruits and watching for a reaction. Your medical history and current physical condition are also taken into account.
Prevention and Treatment
Not consuming the offending fruit is the best way to prevent an allergic reaction. However, cooking the fruit, or processing it, such as canning, before eating it can also prevent itchiness and other symptoms. Symptoms usually subside within a few minutes so treatment is often not necessary, notes the Food Allergy and Anaphylaxis Network. If you suffer a reaction such as tightness in your throat or difficulty breathing, seek medical attention immediately.
References
- U.S. Centers for Disease Control and Prevention: Food and Allergies
- Canadian Food Inspection Agency: Oral Allergy Syndrome
- The Food Allergy and Anaphylaxis Network: Oral Allergy Syndrome
- MayoClinic.com: Food Allergy - Symptoms
- "Journal of Allergy and Clinical Immunology"; Guidelines for the Diagnosis and Management of Food Allergy in the United States: Summary of the NIAID Sponsored Expert Panel Report; Joshua A. Boyce, M.D. et al.; Dec 2010
