What is the Oral Allergy Syndrome?

Watermelon
Getty

Most people are familiar with hay fever and food allergies, but many do not realize there can be a connection. Oral allergy syndrome, also known as a pollen-food syndrome, can cause people who suffer from hay fever to experience symptoms such as an itchy mouth or scratchy throat when eating certain fruits, vegetables, or tree nuts. 

Oral allergy syndrome is caused by allergens that occur in both pollen and certain foods to cross-react, triggering the immune system to mount an allergic response.

People with oral allergy syndrome usually only experience a reaction when eating raw fruits or vegetables as cooking alters the proteins involved. 

Who Is at Risk?

People with a history of allergic reactions to birch, ragweed, or grass pollens can develop oral allergy syndrome, but the condition usually doesn't develop in young children. Rather, older children, teens, and young adults may suddenly develop oral allergies even though they have been comfortably eating the same foods for years. 

Oral Allergy Correlations

As mentioned above, certain foods correlate with particular environmental allergens. For example, if you find you are allergic to various types of melons, you also probably have allergic rhinitis caused by ragweed pollen. When a fresh melon is eaten, a person may experience itching, burning, or stinging sensations of the mouth, throat, and tongue. The symptoms generally last only a few seconds or minutes, as the proteins that cause the symptoms are broken down quickly by saliva.

Other common correlations include:

  • Birch pollen: apple, almond, carrot, celery, cherry, hazelnut, kiwi, peach, pear, plum
  • Grass pollen: celery, melons, oranges, peaches, tomato
  • Ragweed pollen: banana, cucumber, melons, sunflower seeds, zucchini

Because the symptoms usually fade quickly, treatment usually is not necessary or helpful.

People with ragweed allergy may also notice symptoms of OAS with eating fresh bananas and cucumbers.

Diagnosing Oral Allergy Syndrome

A careful history can usually provide enough clues to your doctor that oral allergy syndrome may be present. Sometimes, skin prick tests and oral food challenges can aid in diagnosis. Diagnosis of oral allergy syndrome is reached after taking a patient’s clinical history and, in some cases, conducting skin prick tests and oral food challenges with raw fruit or vegetables.

Anaphylaxis

While anaphylaxis, a serious allergic reaction that compromises breathing, is not very common, it can occur with oral allergy syndrome. Therefore, it is important to obtain a proper diagnosis and find out whether carrying an epinephrine auto-injector is warranted. 

Want to find out more? Read the full-length article on the oral allergy syndrome.

Sources:

Sicherer SH. Clinical Implications of Cross-Reactive Food Allergens. J Allergy Clin Immunol. 2001; 108:881-90.

Ortolani C, Ispano M, Pastorella EA, Ansaloni R, Magri GC. Comparison of Results of Skin Prick Tests and RAST in 100 Patients with Oral Allergy Syndrome. J Allergy Clin Immunol. 1989; 83:683-90.

Sampson HA. Adverse Reactions to Foods. In: Adkinson NF, Yunginger JW, Busse WW, et al, eds. Middleton’s Allergy Principles and Practice. 6th edition. Philadelphia: Mosby Publishing; 2003:1619-1643.

Continue Reading