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Common cutaneous drug reactions

Last reviewed: 30 Oct 2023
Last updated: 22 Aug 2023



History and exam

Key diagnostic factors

  • history of drug exposure
  • skin lesions
  • variable skin reactions within 5 to 15 minutes of drug exposure
  • variable skin reactions within a few hours of drug exposure
  • variable skin reactions within 2 weeks of drug exposure
  • variable skin reactions within months to years of drug exposure
  • previous exposure and reaction to drug
More key diagnostic factors

Other diagnostic factors

  • pruritus
  • associated noncutaneous features
  • pain
Other diagnostic factors

Risk factors

  • virus infections
  • HIV infection
  • HLA-B*5701 polymorphism
  • HLA-B*1502 polymorphism
  • HLA-B*5801 polymorphism
  • female sex
More risk factors

Diagnostic investigations

Investigations to consider

  • blood (whole blood, plasma, serum) drug concentration
  • serum tryptase concentration (anaphylaxis)
  • complement pathway assay
  • histology of lesion biopsy
  • CBC and differential
  • antihistone antibodies to single-stranded DNA (lupus-like syndrome)
  • skin tests (prick tests, intradermal tests, patch tests)
More investigations to consider

Emerging tests

  • drug-specific IgE
  • basophil activation test
  • lymphocyte proliferation assay (LPA/LTT)
  • enzyme-linked immunospot assay (ELISPOT test)

Treatment algorithm


serious cutaneous adverse reactions

nonserious cutaneous adverse reactions


following acute episode



Michael Ardern-Jones, BSc, MBBS, DPhil, FRCP

Associate Professor

Consultant Dermatologist

Faculty of Medicine

University of Southampton




MA-J declares that he has no competing interests.


Dr Michael Ardern-Jones would like to gratefully acknowledge Dr Wei Yann Haw, Dr Anne Holbrook, Dr Hermenio Lima, and Dr Jeffrey K. Aronson, the previous contributors to this topic.


WYH, AH and HL declare that they have no competing interests. JKA is editor of Meyler's Side Effects of Drugs and its annual companion volumes, the Side Effects of Drugs Annuals.

Peer reviewers

Shahbaz A. Janjua, MD

Specialist Dermatologist

Ayza Skin & Research Center




SAJ declares that he has no competing interests.

Craig K. Svensson, Pharm.D, PhD


College of Pharmacy, Nursing, and Health Sciences

Purdue University

West Lafayette



CKS declares that he has no competing interests.

  • Common cutaneous drug reactions images
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  • Guidelines

    • Drug allergy: a 2022 practice parameter
    • Emergency treatment of anaphylactic reactions​
    More Guidelines
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