Allergies occur when your immune system overreacts to substances called allergens. Common allergens that can trigger allergic reactions include pollen, pet dander, and bee venom. People also have allergies to certain foods and medications.
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Signs and Symptoms of Allergies
Allergy symptoms vary depending on the type of allergens.
Allergic rhinitis (commonly known as hay fever), for instance, is associated with the following symptoms:
- Sneezing
- Runny nose
- Congestion
- Itchy eyes, nose, and throat
- Tearing eyes
An allergic food reaction may share some of the above symptoms, but it can also cause:
- Diarrhea, nausea, and vomiting
- Hives, eczema, or itchy skin
- Anaphylaxis, in which a narrowing of the airways makes it difficult or even impossible to breathe
A skin allergy or insect bite can cause the following at the site:
- Redness
- Swelling
- Hives
- Pain
- Itching
The symptoms of a drug allergy may include:
- Hives
- Wheezing
- Light-headedness
- Vomiting
- Swelling of the face or throat[1]
