Symptoms

Signs and symptoms of an allergic reaction can occur within minutes of exposure to an offending allergen. Reactions usually occur within two hours of exposure, but in rarer cases can develop hours later. Specific warning signs, as well as the severity and intensity of symptoms, can vary from person to person and sometimes from attack to attack in the same person.

An anaphylactic reaction can involve any of the following allergy symptoms, which may appear alone or in any combination, regardless of the triggering allergen:

Due to the unpredictability of reactions, early symptoms of an allergic reaction should never be ignored, especially if the person has suffered an anaphylactic reaction in the past. It is important to note that anaphylaxis can occur without hives appearing on the body.

Learn how to handle an anaphylactic reaction on the Treatment page.