A drug allergy is a type of harmful (adverse) reaction to a medicine. A drug allergy is different from other types of adverse reactions because it involves the immune system. It is important for your doctor to find out whether you have a drug allergy or anothe

A drug allergy occurs when your immune system overreacts to something in a medicine.

Use these drug allergy health tools to help make wise health decisions or take action to improve your health.

Symptoms of drug allergies can be mild or llife-threatening and appear within 1 to 72 hours. They include: Hives or welts, rash, swelling, redness, and blisters, or eczema. These are the most common symptoms of drug allergies.

Your doctor will diagnose a drug allergy by asking you questions about the medicines you are or have recently been taking, your past health, and your symptoms (medical history), and by doing a physical exam.

Treatment for drug allergies includes understanding what to do if you have a severe allergic reaction, avoiding the medicine that causes the allergy, and using medicines such as antihistamines for mild symptoms.

Home treatment for a drug allergy includes avoiding medicines that can cause an allergic reaction, relieving symptoms, and knowing what to do if you have a severe reaction.

A list of organizations that provide resources for treating or living with drug allergies.

A list of topics that are related to drug allergies.

A reference list about drug allergies.

A list of authors contributing to the topic of drug allergies.