What You Need to Know About Drug Allergies

What is a drug allergy?
Allergic reactions are the hyper immune response of our immune system to foreign (antigenic) substances. When certain foreign substances are introduced to the body the immune system is triggered. A hyper immune response may result in the symptoms of allergies. Medications are foreign substances and some of their components trigger the immune system.

What are the symptoms of drug allergy?
Allergic reactions from drugs are similar to allergic reactions from food and other substances that we ingest. An individual’s genetic make-up helps determine what they are allergic to and the severity of their allergies. Allergic reactions can be mild or deadly. Mild reactions include itching, rashes, and hives. More serious reactions involve swelling of lips, tongue, and difficulty breathing that can lead to death.

Allergic reactions are different from common side effects of many drugs such as a headache or stomach upset.

What drugs are people most allergic to?
Any drug or a component in a drug can case an allergic reaction. Penicillin and related drugs, sulfa drugs, insulin, and iodine commonly cause allergic reactions. Sometimes it is a component or substances used for packaging or administering the drug that causes the allergy. Components of drugs that commonly cause allergies include dyes, egg proteins, and peanuts. Latex in the packaging of drugs commonly causes allergic reactions.

How is a drug allergy diagnosed?
Most times drug allergies are identified based on the time proximity of the reaction to administration of the drug and patient history. If the drug is stopped and the symptoms also stop then the logical conclusion is that the drug caused the allergic reaction. Skin testing can also be used to verify that the drug is causing the allergy. If it is a drug that the patient needs and there are no other alternatives, careful skin testing can be done to determine if the person is truly allergic to the drug.

What is the treatment for a drug allergy?
The first step is to stop the suspect drug. For skin reactions such as rashes and itching antihistamine creams (for example Benadryl) or steroid creams (for example, hydrocortisone) are used. Oral antihistamines and steroids are used for more bothersome symptoms. Injections of antihistamines and or steroids are given for serious allergic reactions. For life threatening anaphylactic reactions which involve difficulty breathing, epinephrine is given usually intramuscularly.

In situations where a drug is needed and there are no alternatives an allergist can attempt to desensitize the individual by gradually giving very small amounts of the drug and increasing the amount over a time.

What should I do if I have an allergic reaction to a drug?
Contact your doctor if you develop a rash, itching, hives or any symptom related to drug allergy. If your Lip or tongue swells or you have shortness of breath go the emergency room immediately. Do not drive yourself, call 911.

Medically Reviewed by a Doctor on 4/9/2015
Credit: HealthDay

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