The symptoms of an allergic reaction depend on the type and severity of the reaction. Common symptoms of an allergy are sneezing, itching, watery eyes, stuffy or runny nose, swelling, a rash or hives, stomach cramps, and diarrhea.

Some of the symptoms of a severe allergic reaction are fast heart rate, difficulty breathing or shortness of breath, nausea and vomiting, swelling of the lips, tongue, or throat, hives, pale, cool, damp skin, and drowsiness, confusion, or loss of consciousness.