Overview of Allergic Reactions - Overview of Allergic Reactions - Merck Manual Consumer Version
Allergic reactions (hypersensitivity reactions) are inappropriate responses of the immune system to a normally harmless substance.Usually, allergies cause sneezing, watery and itchy eyes, a runny nose, itchy skin, and rash.Some allergic reactions, called anaphylactic reactions, are life threatening.Symptoms suggest the diagnosis, and skin testing can help identify the substance that triggers the allergy but does not predict the severity of a future reaction. Avoiding the trigger is best, but if it is impossible... Читать дальше...