Medically reviewed by Jurairat J. Molina, MD Allergies are an immune system reaction to substances called allergens. The ...

Many allergic reactions and anaphylaxis symptoms are similar because both conditions involve an allergic response from the immune system. Mild allergic reactions cause minimal symptoms ...

An allergy happens when your immune system mistakes a normal, harmless substance for something that can cause illness. Your body then has an allergic reaction to this harmless substance—called an ...

Find out why stress can worsen allergy symptoms. Learn about the cellular chain reaction that occurs in the body and how it ...

An allergic reaction, or when your immune system overreacts to a harmless substance, can sometimes manifest in the form of a rash. An allergy rash can be uncomfortable and lead to infections ...

A food allergy happens when the body's immune system, which normally fights infections, sees the food as an invader. This leads to an allergic reaction. Even if previous reactions have been mild, ...

Ian McKnight is researching the biological mechanisms underlying allergies, with the goal of developing new therapeutics to ...

Bee stings are not just a painful inconvenience; they are the result of a highly evolved biological defense mechanism. When a ...

Mild to moderate signs of food allergy include a swollen face, lips or eyes; hives or welts on your skin; or vomiting. A severe allergic reaction (called anaphylaxis) can cause trouble breathing, ...

Allergic reactions may vary in length ... The body's defense system to protect you from infection and harmful microorganisms. The immune system is capable of waging complex responses to various ...