Anaphylaxis (say "ann-uh-fuh-LAK-suss") is a severe allergic reaction that affects the entire body (systemic).

Symptoms of a severe allergic reaction can start within minutes of eating or being exposed to an allergen. In fewer cases the time frame can vary up to several hours after exposure. Do not ignore early symptoms. When a reaction begins, it is important to respond right away. 

Symptoms of a severe allergic reaction can vary from person to person. The same person can have different symptoms each time they have a severe allergic reaction. Symptoms can include any of the following:

• Skin: hives, swelling (face, lips, tongue), itching, warmth, redness
• Respiratory (breathing): coughing, wheezing, shortness of breath, chest pain or tightness, throat tightness, hoarse voice, nasal congestion or hay fever-like symptoms (runny, itchy nose and watery eyes, sneezing), trouble swallowing
• Gastrointestinal (stomach): nausea, pain or cramps, vomiting, diarrhea
• Cardiovascular (heart): paler than normal skin colour/blue colour, weak pulse, passing out, dizziness or lightheadedness, shock
• Other: anxiety, sense of doom (the feeling that something bad is about to happen), headache, uterine cramps, metallic taste

A severe reaction can take place without hives. Make sure to look out for any of the signs of an allergic reaction.