Last reviewed: 13 Apr 2021
Last updated: 19 Dec 2019



History and exam

Key diagnostic factors

  • presence of risk factors
  • black or Hispanic ancestry
  • new pigmented velvety skin lesions in axillary or flexural areas
  • lesions distributed on the posterior neck, axillae, vulva, umbilicus, inner thighs, and groin
  • weight gain
  • generalised distribution
  • sudden appearance of multiple seborrhoeic keratoses

Other diagnostic factors

  • age >40 years
  • child/young adult
  • female sex
  • acrochordons (skin tags)
  • acral distribution
  • pruritus
  • mucosal or palmoplantar lesions
  • weight loss

Risk factors

  • obesity
  • insulin resistance
  • positive family history of AN or genetic syndrome
  • family history of diabetes mellitus
  • malignancy
  • medication

Diagnostic investigations

Investigations to consider

  • fasting blood glucose
  • fasting blood insulin
  • abdominal CT
  • skin biopsy

Treatment algorithm


Consultant Dermatopathologist

Southern California Permanente Medical Group

Sunset Medical Center

Los Angeles



DSC declares that he has no competing interests.

Dr David Cassarino would like to gratefully acknowledge Dr Laura Westerling for her contribution to this topic. LNW declares that she has no competing interests.

Peer reviewersVIEW ALL

Assistant Professor of Dermatology

Department of Dermatology

Yale University

New Haven



CK declares that she has no competing interests.

Consultant Dermatologist

Department of Dermatology

Queen's Medical Centre

Nottingham University Hospitals




JE declares that he has no competing interests.

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