4.2.1 Alopecia Areata

Grading & Level of Importance: B

Review:
2022

W. Burgdorf, Munich; S. Chee, A. Salam, J. McGrath, London;
Revised by J White, V del Marmol, Brussels

ICD-11

ED70.2

Synonyms

Spot baldness, patchy alopecia, autoimmune hair loss.

Definition

Reversible, non-scarring, usually localised but also generalized hair loss.

Aetiology & Pathogenesis

Present in all ethnic populations. May affect 0.1% of the population.
Autoimmune process with lymphocytic T-helper and T-cytotoxic cell subsets infiltrate around anagen hair bulb. Association with other autoimmune diseases; Down syndrome.

Signs & Symptoms

Macroscopically non-inflamed, non-scarring loss of hair in circular shapes with solitary, multiple or diffuse patterns. Exclamation mark hairs. Sometimes associated nail changes (pitting) or complete nail loss.

Localisation

Most easily identified in hairy areas such as the scalp or beard region, or body hair.

Classification

According to extent of hair loss:


Alopecia areata: solitary or multiple areas of hair loss.
Alopecia totalis: loss of all scalp hairs.
Alopecia universalis: loss of all scalp and body hairs.

Laboratory & other workups

Association with atopy with increased IgE (worse prognosis) and autoimmune thyroiditis (TAK /MAK). Syphilis serology (where there are multiple small patches clinically) to exclude moth-eaten alopecia of secondary syphilis. Fungal culture if diagnostic doubt. Anti-streptokinase titre.

Dermatopathology

Not usually required. Perifollicular lymphocytic infiltrate around anagen follicles with apoptosis of follicular keratinocytes and formation of dystrophic hair shafts.

Course

Focal lesions have a high spontaneous remission rate (30% within 6 months, 50% with 1 year, 80% within 3 years). Widespread disease has low spontaneous remission rate (Factors conveying a poor prognosis include positive family history, involvement of occipital scalp hairline (ophiasis type), widespread disease, longer duration (onset in childhood) and atopy.

Complications

Loss of eyebrows and eyelashes with chronic conjunctivitis, nail involvement (twenty nail dystrophy), association with autoimmune thyroiditis, vitiligo, pernicious anemia (other autoimmune disorders less common), psychosocial problems with persistent alopecia are common.

Diagnosis

Clinical diagnosis in most cases.

Differential diagnosis

Alopecia specifica in secondary syphilis, trichotillomania, early stage of scarring alopecias (such as deep trichophyton infections).

Prevention & Therapy

Await spontaneous regrowth. Small lesions can be treated with high-potency topical corticosteroids or intralesional corticosteroids. More widespread forms may respond to topical immunotherapy with diphenylcyclopropenone. In severe cases, systemic corticosteroid pulsed therapy can be considered. Other evidence-based treatment are not available but third line treatments may include methotrexate, zinc and phototherapy. Wigs, permanent make-up for eyebrows and self-help groups.

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