Drug allergies

Alternative Names

Allergic reaction – drug (medication); Drug hypersensitivity; Medication hypersensitivity

Definition of Drug allergies

Drug allergies are a group of symptoms caused by an allergic reaction to a drug (medication).

Causes, incidence, and risk factors

Adverse reactions to drugs are common, and almost any drug can cause an adverse reaction. Reactions range from irritating or mild side effects such as nausea and vomiting to life-threatening anaphylaxis.

Signs and tests

An examination of the skin and face may show hives, rash, or angioedema (swelling of the lips, face, or tongue). Decreased blood pressure, wheezing, and other signs may indicate an anaphylactic reaction.


The treatment goal is to relieve symptoms and prevent a severe reaction.

Expectations (prognosis)

Most drug allergies respond readily to treatment. A few cases cause severe asthma, anaphylaxis, or death.


Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Paula J. Busse, MD, Assistant Professor of Medicine, Division of Clinical Immunology, Mount Sinai School of Medicine, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 6/29/2010

Allergic reactions to medication
Dermatitis, contact
Dermatitis, pustular contact
Drug rash, Tegretol
Fixed drug eruption
Fixed drug eruption, bullous
Fixed drug eruption on the cheek
Drug rash on the back

ADAM Medical Encyclopedia

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