Itchy mouth or throat when you eat raw fruits, vegetables or nuts? These symptoms are both signs of oral allergy syndrome (OAS), sometimes called pollen food syndrome.
Itchy mouth or throat when you eat raw fruits, vegetables or nuts? These symptoms are both signs of oral allergy syndrome (OAS), sometimes called pollen food syndrome.
“Having this reaction might mean you feel anxious about having an allergic reaction to foods,” says
, Clinical Content Reviewer. “You may avoid eating them and miss out on variety and health benefits, or you might worry about developing allergies to other foods - so it could put you off wanting to try different dishes or go to restaurants. But mostly, OAS symptoms are mild and there’s plenty you can do to get a handle on the condition.”OAS happens when you have an allergic reaction immediately after eating certain raw fruits, vegetables or nuts. Your allergy antibodies mistake certain proteins in these plant foods for pollen and this triggers a reaction, meaning you get itching in your mouth and throat, and possibly tingling and mild swelling.
OAS is a type of
. The difference between OAS and other food allergies is that OAS is triggered by allergens in raw fruit, veg and nuts that are very similar to the allergens in pollen. Other foods, such as dairy and seafood, don’t cause OAS but can trigger different symptoms - so it’s important to know which type of allergy you have and how to treat it.With OAS, you can have a reaction to pretty much any raw fruit, vegetable or nut. But the most common trigger foods are apples, peaches, kiwis, hazelnuts and almonds. Most people with OAS find they get a reaction to 1 or 2 foods but you might find you develop reactions to more foods over time.
It’s the most common type of food allergy in adults, although it can affect children too.
OAS is caused by a pollen allergy - the same allergy that causes hay fever symptoms like a runny nose and itchy eyes. So if you have
, you're also more likely to have OAS, and the other way round. But you could have OAS and not get hay fever symptoms, or just get very mild ones.Rarely, OAS can affect people with rubber latex allergy, rather than pollen, because the protein structure of latex is similar to the fruit pollen structure in certain foods, like mango and melon.
More research is needed but scientists think these factors could be at play:
Even if your symptoms are mild, OAS can feel worrying, especially the first time it happens. The good news is there’s plenty you can do to manage it.
First, identify the food that triggers a reaction - often it will be obvious but if not, a
could help. Once you’ve pinpointed the food, the golden rule is to avoid eating it raw. There are some other useful tips that might also help.Remember that in most cases, OAS symptoms are mild and should settle down within an hour. Here’s what can help:
It’s unlikely you’ll have a severe allergic reaction (
) but if it does happen, it may be life-threatening. Seek emergency medical help immediately if:If you have an adrenaline auto-injector, use it as soon as you think you might be having a severe allergic reaction and call an ambulance immediately.
There are a few things that can dial up your chance of a severe reaction:
Try our
– designed by doctors to help you learn more about your symptoms. If you think you might have OAS, speak to your doctor, who can advise you on next steps.Your doctor might be able to diagnose OAS by asking you a few questions. But if things aren’t clear-cut, you might need to see an allergy specialist. To find out what’s going on, the specialist might recommend skin testing or a food challenge – where you eat a food or put a drop of liquid on your skin and they check your reaction.
You should be able to live with OAS by following the tips above. But if you’re at risk of severe reactions, your doctor might prescribe adrenaline auto-injector devices (AAIs), or adrenaline pens. These contain adrenaline (also known as epinephrine), which you inject into your thigh muscle as soon as a suspected severe reaction starts – the medication works to stop the reaction becoming life-threatening. Your doctor will take you through exactly how and when to use it.
“So far, there’s no proven cure for OAS, but knowing your food triggers means you can prevent symptoms. Doctors might consider
if you have very severe symptoms. This is sometimes used for people with pollen allergies that cause hay fever or asthma, and works by giving you small amounts of the allergen either by injection or orally to desensitise you to it. But although it’s been shown to work in asthma and hay fever, studies so far haven’t proven whether it works or not for OAS.”– Dr Adiele Hoffman“As we often diagnose OAS based on your symptoms alone, food and symptom diaries can be really helpful to identify which foods cause a reaction in you. Try using the Healthily
to figure out what your triggers are.” – Dr Adiele HoffmanImportant: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.