Oral allergy syndrome (OAS) is a common condition that doesn't usually require medical treatment. The best way to manage it is to avoid the foods that trigger it. In some cases, peeling or cooking the food can reduce the effects. Taking an antihistamine may also help relieve symptoms.
Fruits, vegetables, and nuts can all cause OAS. This is because they contain proteins that are similar to the proteins found in pollen. When these proteins enter the body, it reacts as if it were exposed to an allergen from a tree, herb, or plant. It's like a puzzle piece that's close enough to the right shape to fit in the right place, even though it isn't actually the right piece.
If you have hay fever and experience itching in your mouth or throat after eating certain raw fruits or vegetables and some nuts, you may have food pollen allergy syndrome (PFAS). PFAS is caused by allergens found in both pollen and certain foods. If you have seasonal allergies and want to know which other foods can make them worse, these are known as trigger foods.