Makindo Medical Notes

Related Subjects: |Atopic Eczema/Atopic Dermatitis |Psoriasis |Alopecia Areata |Alopecia

Exam shows circular area of nonscarring alopecia incidentally found in an adult patient

About

• Alopecia areata is an autoimmune condition characterized by patchy hair loss.
• Affects the hair follicles and sometimes the nails
• Affects 1 in 1000 people worldwide; in the USA
• Affects patients at all ages including children

Aetiology

• Alopecia areata is an organ-specific autoimmune disease targeting hair follicles
• Dystrophic changes of anagen follicles along with rapid progression of hair follicles from anagen to catagen and telogen phases are observed

Alopecia areata (AA) is an autoimmune condition causing sudden, non-scarring hair loss. It affects about 2% of the population worldwide and can occur at any age, including children. 🧑‍🦱➡️🕳️

About

• Organ-specific autoimmune disease targeting hair follicles.
• Characterised by patchy hair loss, but any hair-bearing area can be affected.
• Can involve the nails (pitting, ridging) in ~10–20% of cases.

Aetiology

• Autoimmune T-cell attack on anagen hair follicles.
• Leads to premature conversion of follicles into catagen/telogen phase.
• Genetic predisposition with environmental triggers (stress, illness).

Associations

• Other autoimmune diseases – thyroid disease, vitiligo, pernicious anaemia, type 1 diabetes.
• Atopy (eczema, asthma, allergic rhinitis).
• Chromosomal disorders – Down syndrome, Turner syndrome.

Clinical Features

• Round/oval patches of hair loss; scalp most common, but beard, eyebrows, eyelashes may be affected.
• Skin appears normal (non-scarring).
• Short broken “exclamation mark hairs” at lesion margins.
• Nail changes in ~10–20% (pitting, trachyonychia).
• Severe forms:
  • Alopecia totalis – complete scalp hair loss.
  • Alopecia universalis – total body hair loss.

Poor Prognostic Factors

• Childhood onset.
• Extensive disease (totalis/universalis).
• Ophiasis pattern (band-like loss at occiput/temples).
• Nail involvement.
• Family history or associated autoimmune disease.

Investigations

• Diagnosis is usually clinical 👀.
• Blood tests only if suspicion of associated conditions (e.g. TSH for thyroid disease).
• Dermatology may use dermoscopy (yellow dots, exclamation hairs).

Management

• Limited disease: potent topical corticosteroids (e.g. clobetasol) or intralesional triamcinolone.
• Extensive disease: consider referral for immunotherapy (e.g. diphencyprone), JAK inhibitors, or phototherapy (dermatologist-led).
• Supportive: wigs, hair camouflage sprays/fibres, psychological support.
• Half of patients experience regrowth within 1 year, but relapses are common 🔄.

References

• British Association of Dermatologists – Alopecia Areata
• UpToDate: Alopecia Areata