A hazelnut allergy is a common type of tree nut allergy that usually begins during childhood. Avoiding hazelnuts is the best way to prevent associated allergic reactions. Tree nut allergies are ...

Allergy symptoms depend on the type of allergy but may include sneezing, itchy skin, or swelling. Some allergies can cause anaphylaxis, which can be life threatening and requires immediate treatment.

An allergy is an immune system overreaction to a substance that would otherwise pose no harm. Doctors may use a physical examination, skin tests, and blood tests to diagnose allergies. Different types ...