In this article, Dr. Babini Shah, attending physician at LloydsPharmacy Online Doctor, attempts to demystify a common but little-known allergy condition: Pollen Food Syndrome.
From Dr Bhavini Shah, GP at LloydsPharmacy Online Doctor
Pollen food syndrome (PFS), also known as oral allergy syndrome, is a hypersensitivity reaction to plant foods such as fruits, vegetables, and nuts. Ingesting these foods raw can cause mild irritation, such as itching of the mouth, lips, and throat.
A recent survey conducted by LloydsPharmacy Online Doctor found that while 50% of respondents said they suffered from hay fever, 71% had never heard of PFS and generally avoided foods that cause PFS. Only 12% felt “very confident” in making the identification. This lack of awareness is concerning, especially considering that approximately 2% of the population, or approximately 1 in 50 people, is affected by PFS.
PFS often occurs in people who experience hay fever, but this is not always the case. PFS is caused by the protein structure of many plant-based foods, such as fruits and cereals. These structures are very similar in shape to the pollen of trees, grasses, and weeds that cause hay fever.
Your immune system doesn't always recognize the difference in structure between the pollen you breathe in from trees and the pollen in the plant foods you eat. Basically, PFS causes your immune system to recognize the food proteins you eat as allergens, triggering an allergic reaction and causing symptoms similar to hay fever.
Foods that cause PFS
Raw fruits, raw vegetables, and raw nuts are the types of foods that cause PFS. Almost any fruit, vegetable, or nut can cause a reaction, but raw apples, fresh peaches, kiwi, hazelnuts, and almonds are especially common triggers. On average, PFS patients should avoid four trigger foods.
Recognize the symptoms of PFS
Symptoms of PFS are usually mild and tend to occur within 10 minutes of eating the food you are allergic to. These may include redness, itching, and mild swelling of the lips, tongue, inside of the mouth, ears, and throat. Some people notice symptoms just by preparing food. For example, food particles in the air can cause sneezing, runny nose, and eye irritation, and peeling fruits and vegetables can cause dermatitis.
Although rare, more extreme symptoms such as nausea, vomiting, difficulty swallowing, and difficulty breathing may occur. In such cases, it is important to seek urgent medical treatment.
Management of PFS reactions
Mild PFS symptoms generally resolve within an hour without treatment. Symptoms can be alleviated by simply stopping food intake and drinking water. However, if you are concerned or your symptoms are particularly unpleasant, you can also take a non-drowsy antihistamine.
If you are taking antihistamines and your symptoms do not improve, you should see your doctor. If you have a food allergic reaction that affects your breathing or circulation, such as causing fainting, don't rely on antihistamines or asthma inhalers. Instead, consult your health care provider immediately.
Prevention of PFS reactions
PFS reactions can be prevented by avoiding triggering foods in their raw state. When cooked well or canned, the allergens are denatured and no longer cause problems. This means that soups containing allergic foods may not cause symptoms, but very gently cooked vegetable stir-fries may cause problems.
Some people can tolerate certain types of the same food. For example, one type of apple may cause a reaction, while another type may not.
If your symptoms are triggered by food preparation, wearing gloves or peeling the allergic food under running water can be an effective workaround.
If you need to remove certain culprit plant foods from your diet, try replacing them with other acceptable foods. You should aim to eat at least five types of fruits and vegetables a day to ensure your diet is rich in fiber, vitamins, and minerals.
If you are prescribed allergy medications for other allergies, such as asthma or hay fever, you should continue to take these medications because they can help control the symptoms of PFS. If you have experienced severe reactions in the past, such as anaphylaxis or difficulty breathing, you may be prescribed an epinephrine pen.
Anaphylaxis can cause swelling of the lips and tongue, difficulty breathing, collapse, and loss of consciousness. In some cases, anaphylaxis can be fatal and should always be treated as a medical emergency.
Diagnosis of PFS
If you have symptoms of PFS, you should make an appointment to see your doctor. PFS can often be diagnosed without additional tests. However, you may be referred to undergo blood tests or skin prick tests to confirm the diagnosis.
PFS is a condition that requires recognition and understanding. If you suspect you have PFS, don't hesitate to seek medical advice. Remember, knowledge is the first step to managing any health condition.
About the author
Dr Bhavini Shah is Head of Clinical Audit at LloydsPharmacy Online Doctor and also works as a GP in North West London. Dr. Shah received his medical degree from University College London. She completed her general medicine training at Imperial College Hospital.