An allergy is a reaction by your immune system that your body detects as foreign. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are:
- Pollen
- Dust mites
- Mold spores
- Pet dander
- Food
- Insect stings
- Medicines
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 avoidance of substances that cause the reaction.