Allergic reactions are sensitivities to a specific substance, called an allergen , that is contacted through the skin, inhaled into the lungs, swallowed, or injected.
Allergic reactions are common. In fact, the immune response that causes an allergic reaction is similar to that which causes hayfever. Most reactions happen soon after contact with an allergen.
Many allergic reactions are mild and can be treated at home, while others can be severe and life-threatening. They often occur more frequently in people with a family history of allergies .
Substances that don’t bother most of us (such as venom from bee stings and various foods, medications, and pollens) can trigger allergic reactions in some people.
While first-time exposure may only produce a mild reaction, …