Alopecia areata
Summary
Definition
Alopecia areata (AA) is an autoimmune disease that causes inflammation of the hair follicles resulting in non-scarring hair loss, affecting scalp and body hair.[1][2] Typically, one or more small round patch of hair loss without atrophy is noticed. This patchy hair loss may regrow spontaneously. In other cases there can be extensive patchy hair loss and in rare cases there is total body hair loss (alopecia areata universalis), or total scalp hair loss (alopecia totalis).[Figure caption and citation for the preceding image starts]: Alopecia areataProvided by Paradi Mirmirani, MD [Citation ends].
History and exam
Key diagnostic factors
- hair loss
- non-scarring alopecia
- exclamation mark hairs
- normal underlying skin in bare areas
- nail pitting
Other diagnostic factors
- autoimmunity
Risk factors
- autoimmune disease
- family history of autoimmune disease
Diagnostic investigations
1st investigations to order
- clinical diagnosis
- positive hair pull test
Investigations to consider
- skin biopsy
- trichoscopy
Treatment algorithm
limited hair loss (treatment desired)
limited hair loss (no treatment desired)
extensive hair loss (treatment desired)
extensive hair loss (no treatment desired)
Contributors
Authors
Fong Seng Lim, MBBS, MMed (FM), FAMS
Senior Consultant
Department of Family Medicine
National University Health System
Singapore
Disclosures
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
Singapore
Disclosures
MS declares that she has no competing interests.
Acknowledgements
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
Minneapolis
MN
Disclosures
MH declares that she has no competing interests.
Ralph M. Trueb, MD
Associate Professor
Department of Dermatology
University Hospital of Zurich
Zurich
Switzerland
Disclosures
RMT is an author of a number of references cited in this topic.
Differentials
- Trichotillomania
- Tinea capitis
- Telogen effluvium
More DifferentialsGuidelines
- British Association of Dermatologists' guidelines for the management of alopecia areata 2012
- EEMCO guidance for the assessment of hair shedding and alopecia
More GuidelinesPatient leaflets
Alopecia areata
More Patient leaflets
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