Oral allergy syndrome (OAS), also known as pollen-food allergy syndrome (PFAS), is a form of food allergy triggered by fruits, vegetables, and nuts. It normally causes mild allergic reactions confined to the mouth, lips, and throat. This condition arises due to a cross-reaction with plant pollens, such as those from trees, grasses, or weeds.
OAS is primarily common among people allergic to grass, trees, and weed pollen, which are often linked to seasonal allergies or allergic rhinitis. Kids below the age of three are rarely affected by this condition since it takes several years of exposure to pollen to trigger such allergies.
Although the precise number of people diagnosed with oral allergy syndrome is unknown, it is the most prevalent food allergy among grownups. According to studies, OAS is thought to affect 47% to 70% of those with pollen allergies.
In most cases, oral allergy syndrome is not dangerous. Many people only experience mild swelling or itching because of their allergic reaction. Anaphylaxis is a serious allergic reaction that affects no more than 2% of individuals with OAS. This condition can be fatal and causes breathing difficulties.
OAS occurs when the immune system mistakenly identifies some foods (trigger foods) as harmful substances. This immune response causes itching or swelling in the lips and mouth. Normally, stomach acid neutralizes the proteins responsible, preventing the reaction from progressing beyond the mouth.
Oral allergy syndrome symptoms often develop shortly after consuming trigger foods. They can include:
Other less common symptoms that can affect other body parts are:
OAS is caused by proteins in certain vegetables, fruits, and nuts that mimic the structure of pollen proteins. This triggers an immune response that is like a pollen allergy. The specific foods that cause OAS vary depending on your other allergies.
It’s comparable to a puzzle piece that appears to fit, even though it doesn’t. While some individuals react to foods linked to their pollen allergies, others may experience food reactions without a corresponding pollen allergy.
The likelihood of reacting to specific foods depends on the type of pollen allergy:
Birch tree pollen:
Grass pollen:
Ragweed Pollen:
Mugwort pollen
Additional foods associated with oral allergies are berries, figs, citrus fruits, grapes, pineapples, mangoes, and pomegranates.
Oral allergy syndrome is diagnosed by a medical professional (mostly an allergist) based on your symptoms.
An allergist may use the following tests to confirm OAS:
OAS does not have a specific cure. Once you cease consuming the trigger food, any reactions you may have should fade away on their own in approximately half an hour. An antihistamine can help manage symptoms, though mild reactions often subside faster than the medication takes effect.
People with OAS can usually consume most foods without issues. Reactions are often limited to specific vegetables, fruits, or nuts.
Prevention
Avoiding foods that trigger reactions is the only way to prevent oral allergy syndrome. You may also be able to minimize or avoid a reaction by considering these measures:
Outlook / Prognosis
Severe allergic reactions are uncommon in cases of oral allergy syndrome. You should consider avoiding a particular food if the symptoms it causes concern you.
For some, OAS can disappear even though there is no known cure. Your body can adapt to foods that previously caused reactions, allowing you to tolerate them in the future.
While most people find oral allergy syndrome annoying, some experience severe side effects. If you are concerned about food allergies, consult an allergist or healthcare professional. You could still enjoy your favourite foods or find suitable alternatives that won’t cause discomfort.
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