An allergic reaction to tree nuts can cause a variety of signs and symptoms that range from mild to severe and may be systemic (affecting the whole body) or localized (affecting a single body part or organ). Reactions may include skin involvement (e.g., rashes, swelling, itching); eye discomfort (e.g., itchy, watery, and/or swollen eyes); respiratory difficulties (e.g., shortness of breath, coughing, wheezing, throat swelling, hoarseness); gastrointestinal issues (e.g., nausea, vomiting, cramping, diarrhea); cardiovascular changes (e.g., drops in blood pressure, increased heart rate); and neurological responses, although rare (e.g., fainting, seizures, dizziness).
Most signs and symptoms occur within minutes of exposure to tree nuts, although a delayed response of up to 2 hours is possible. Exposure to tree nuts usually happens through ingestion — skin contact or inhalation rarely causes an allergic reaction. When the allergic reaction is very severe and/or involves more than one organ system, it is called an anaphylactic reaction, which can be life-threatening without prompt treatment.[1][2]