Allergies arise if the body’s immune system overreacts to foreign substances that are usually harmless such as pollen or certain foods. Many allergens can be avoided. More persistent symptoms can be treated with medication.

Allergies from A to Z

Popular in Allergies

  • Photo of a man having a sneezing fit


    Allergies arise if the body's immune system overreacts to substances (allergens) that are usually harmless, such as pollen. The symptoms are sometime...

  • Photo of a hairdresser styling a woman’s hair

    Allergic contact dermatitis

    In allergic contact dermatitis, the immune system overreacts to certain substances – sometimes to very small amounts – that generally don’t cause sev...

  • Photo of a woman choosing a piece of cake at a café

    Food allergies

    In food allergies, even small amounts of the food can be enough to trigger an allergic reaction (e.g. itching and swelling in the mouth and throat, o...

  • Photo of a man doing laundry

    Dust mite allergies

    Dust mite allergies usually develop in childhood or puberty. The symptoms (such as sneezing) aren’t actually caused by the dust itself, but by substa...

  • Insect venom allergies

    Insect venom allergies

    We all get stung or bitten by insects every now and then – and most people end up with a small, red, itchy bump as a result. But those who are allerg...

  • Photo of a woman blowing her nose

    Hay fever

    If you have hay fever, you're not alone: About 1 in 4 people have this allergy. Various medications and allergen-specific immunotherapy often provide...