A food allergy refers to an abnormal immune system response triggered by the interaction of food-specific proteins and antibodies against them. Certain foods are more likely to trigger allergies than others. An allergy to citrus fruits is relatively uncommon, as are allergies to most fruits and vegetables. Nonetheless, citrus fruit allergies can and do develop. As with other food allergies, the symptoms of a citrus allergy can range from mild to severe.
Oral Allergy Syndrome vs. Citrus Allergy
Most people who experience an allergic reaction to citrus fruit have oral allergy syndrome (OAS), also known as pollen-food syndrome. With this condition, antibodies formed due to an allergy to airborne pollens also react with proteins found in certain fruits and vegetables. People who are allergic to grass pollen, for example, may develop oral allergy symptoms when eating melon, citrus fruit, peaches, celery, potatoes, tomatoes and/or peanuts. Although OAS appears to be the most common cause of allergic reactions to citrus fruit, it's possible to have an allergy specifically to citrus fruit -- what is often termed a "true" citrus allergy. As all citrus fruits are closely related and share many proteins in common, people who react to one type of citrus fruit typically react to other citrus fruits as well.
OAS symptoms are the same, regardless of the triggering food. Symptoms are almost always triggered by eating uncooked fruit or vegetables. Upon putting the offending food into the mouth, tingling and itchiness of the lips, mouth, tongue and throat ensue. Swelling of these same tissues can also occur. Not surprisingly, these symptoms are similar to what occurs in the nose with hay fever. In most cases, OAS symptoms are limited to the mouth and throat. However, the American College of Allergy, Asthma and Immunology reports that OAS symptoms progress to systemic symptoms in roughly 9 percent of cases, and life-threatening anaphylaxis in 1.7 percent.
Systemic symptoms of an allergic reaction to citrus fruit can develop within minutes, or be delayed for up to 2 hours. Symptoms can involve the skin, digestive system and/or respiratory system, and range from mild to severe. Possible symptoms include: -- hives and itchiness -- nausea, vomiting, abdominal cramps and diarrhea -- throat tightness, wheezing and difficulty breathing
These symptoms can progress to life-threatening anaphylaxis, with low blood pressure, a racing heart, dizziness or fainting, and severe respiratory distress.
Treatment and Precautions
If you suspect you are allergic to citrus fruit, see your doctor for evaluation and testing to confirm the diagnosis. Avoidance of triggering foods is the cornerstone of treatment for any food allergy, including an allergy to citrus fruits. If you have citrus-related OAS, you may be able to tolerate cooked citrus fruits and juices, as the cooking process usually destroys the triggering proteins. If you have multiple food allergies related to OAS, your doctor might recommend allergy shots, or allergen immunotherapy, to the pollens you are sensitive to as a way of reducing your pollen- and food-related allergy symptoms. Other medications and treatments may be recommended, depending on your individual health history and current situation.
Seek emergency medical attention if you develop any symptoms that might indicate the development of anaphylaxis, which can progress very quickly.
Reviewed and revised by: Tina M. St. John, M.D.
- American College of Allergy, Asthma and Immunology: Oral Allergy Syndrome
- Allergy UK: Oral Allergy Syndrome or Pollen-Food Syndrome
- PLoS One: Citrus Allergy from Pollen to Clinical Symptoms
- Canadian Medical Association Journal: Oral Allergy Syndrome
- American Academy of Allergy, Asthma and Immunology: Oral Allergy Syndrome (OAS)
- Merck Manual Professional Version: Anaphylaxis