While peanuts get most of the attention as far as food allergies are concerned, in fact they're not the only type of nut that people may be allergic to. Tree nut allergies include allergic reactions to cashews, walnuts, almonds, pecans, macadamia nuts, pistachios, and other types of nuts. Most reactions are caused by walnuts and cashews, although it is possible to be allergic to any type of tree nut.
Skin contact with nut residues or the smell of nuts may trigger an allergic reaction in someone with a severe allergy. The symptoms of the allergy are caused by the immune system mistakenly identifying the substance as harmful to the body.
The symptoms of a tree nut allergy are similar to those experienced by those with peanut allergies. Those with allergies to tree nuts tend to experience severe reactions such as anaphylaxis, a potentially life-threatening reaction. This reaction causes severe breathing difficulties and cardiac arrhythmia, among other symptoms. This symptom is usually treated with injectable epinephrine, often carried in an Epi-Pen or similar device. Without treatment, anaphylactic shock can be fatal.
Other potential symptoms include hives, welts, and other skin reactions. These tend to be red and warm to the touch. Areas that have come in contact with the allergen may become itchy, swollen, or tingly. A response similar to an allergy attack, particularly with wheezing and coughing, is also a common symptom of a tree nut allergy. Dizziness, itchy or watery eyes, sneezing, and a runny nose may be other signs of a tree nut reaction. Other symptoms are gastrointestinal, including an upset stomach and diarrhea.