allergy: Quick Facts

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Last updated

Nov. 8, 2026

News •

One-third of babies diagnosed with peanut allergy don't actually have one, study hints • Nov. 5, 2026, 6:30 AM ET (Live Science)

Many diagnosed with a peanut allergy don’t realize they may not have it anymore • Nov. 4, 2026, 5:00 PM ET (Washington Post)

Facts

Also Known As	hypersensitivity • allergenic disease

Photos and Videos

Red, patchy rash with raised areas on human skin, showing an allergic contact dermatitis reaction caused by exposure to poison ivy.

This medical illustration explains a systemic anaphylactic response to bee venom in someone with type I hypersensitivity. It shows a bee sting injecting venom into the skin, which then enters the bloodstream and spreads throughout the body. The diagram highlights how the immune system reacts, including mast cell activation and the release of substances that cause symptoms such as swelling, low blood pressure, breathing difficulty, digestive issues, and skin reactions. The human figure is annotat

Close-up of a patient's back showing several red, raised patches within purple dashed rectangles, indicating positive allergic reactions from a skin test.

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Topics

food allergy type IV hypersensitivity type III hypersensitivity MSG symptom complex type II hypersensitivity photosensitivity pigeon fancier’s lung malt worker’s lung humidifier fever What causes allergies?infectious disease foodborne illness motion sickness necrosis blister mental disorder cardiovascular disease nervous system disease digestive system disease nutritional disease

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Key People

Charles Richet.

Charles Richet

French physiologist

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