Alopecia areata

Last reviewed: 27 Apr 2022
Last updated: 11 Mar 2021



History and exam

Key diagnostic factors

  • hair loss
  • non-scarring alopecia
  • exclamation mark hairs
  • normal underlying skin in bare areas
  • nail pitting
More key diagnostic factors

Other diagnostic factors

  • autoimmunity
Other diagnostic factors

Risk factors

  • autoimmune disease
  • family history of autoimmune disease
More risk factors

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
  • positive hair pull test
More 1st investigations to order

Investigations to consider

  • skin biopsy
  • trichoscopy
More investigations to consider

Treatment algorithm


limited hair loss (treatment desired)

limited hair loss (no treatment desired)


extensive hair loss (treatment desired)

extensive hair loss (no treatment desired)



Fong Seng Lim, MBBS, MMed (FM), FAMS

Senior Consultant

Department of Family Medicine

National University Health System



FSL served on the executive committee in the council of the College of Family Physicians Singapore until 2019.

Miny Samuel, PhD

Assistant Director

Research Support Unit

Yong Loo Lin School of Medicine

National University of Singapore



MS declares that she has no competing interests.


Dr Fong Seng Lim and Dr Miny Samuel would like to gratefully acknowledge Dr Richard A. Strick, Dr Jack Green, and Dr Paradi Mirmirani, previous contributors to this topic. RAS is an honorary member of the National Alopecia Areata Foundation (NAAF) clinical scientific advisory board. JG is an author of a reference cited in this topic. PM declares that he has no competing interests.

Peer reviewers

Maria Hordinsky, MD

Professor and Chair

Department of Dermatology

University of Minnesota




MH declares that she has no competing interests.

Ralph M. Trueb, MD

Associate Professor

Department of Dermatology

University Hospital of Zurich




RMT is an author of a number of references cited in this topic.

  • Alopecia areata images
  • Differentials

    • Trichotillomania
    • Tinea capitis
    • Telogen effluvium
    More Differentials
  • Guidelines

    • British Association of Dermatologists' guidelines for the management of alopecia areata 2012
    • EEMCO guidance for the assessment of hair shedding and alopecia
    More Guidelines
  • Patient leaflets

    Alopecia areata

    More Patient leaflets
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