Although peanut allergies get the most attention, many people are allergic to tree nuts and not to peanuts. This category includes walnuts, cashews, pistachios, and many other forms of nuts. According to researchers, a child with a peanut allergy has a 30% to 60% chance of developing a tree nut allergy, although the rates are much lower for those without peanut allergies.
While most people with tree nut allergies experience reactions to several different types of tree nuts, others have allergies to a specific type of nut, with walnut allergies being the most common. Even if you are allergic to just one kind of nut, it is safest to avoid all types, because the processing of tree nuts lends itself to cross-contamination.
Walnut allergies are caused by an immune reaction to the protein contained in the nut. These allergies can be life-threatening or prompt less severe symptoms. Many people with a walnut allergy experience a reaction with any form of the nut, and even to residues or walnut dust in the air. Others are only allergic to eating uncooked walnuts, and can eat cooked dishes containing walnuts. Some know they have a walnut allergy but continue to eat the nut because the symptoms are not severe, although this is not recommended.
Symptoms of a walnut allergy include itching, rashes or hives, difficulty breathing, and swelling or tingling (especially around the mouth or any other body part that comes in contact with the nut). Itchy, watery eyes, coughing, and wheezing are common symptoms of a food allergies. Gastrointestinal symptoms are also common, including cramping, bloating, and diarrhea. Those with a severe walnut allergy may experience a significant drop in blood pressure, heart arrhythmia, and anaphylactic shock, a life-threatening condition that must be treated immediately with epinephrine.