Allergy
An allergy is an immune system reaction to substances that are typically harmless to most people, ranging from mild irritation to life-threatening emergencies.
Overview
An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies are often sensitive to more than one thing. Substances that often cause reactions include:
- Pollen
- Dust mites
- Mold spores
- Pet dander
- Food
- Insect stings
- Medicines
Causes
Normally, your immune system fights germs as your body's defense system. In most allergic reactions, however, it is responding to a false alarm. Genes and the environment probably both play a role.
Symptoms & Diagnosis
Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Allergies can range from minor to severe. Anaphylaxis is a severe reaction that can be life-threatening.
Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions.