Anaphylaxis is a severe and potentially life-threatening allergic reaction requiring immediate medical attention. Symptoms of anaphylaxis can include difficulty breathing, swelling of the throat, hives, itching, nausea, vomiting, dizziness, and a drop in blood pressure. Anaphylaxis is commonly caused by various triggers, including allergies to certain foods (such as peanuts or shellfish), insect stings, medications, and latex.