Drug Allergy

  • Medical Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

View 10 Common Allergy Triggers

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 Michael Manning, MD; American Board of Allergy & Immunology


RxList.com. Rare-Allergic Drug Reactions.

UpToDate. Drug allergy: Classification and clinical features.

Medically Reviewed by a Doctor on 4/9/2015

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  • Drug Allergy - Symptoms

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  • Drug Allergy - Diagnosis

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  • Drug Allergy - Treatment

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  • Drug Allergy - Preparedness

    If you have a known drug allergy, how are you prepared to handle an emergency or possible exposure?

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  • Drug Allergy - Drugs

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