Alopecia areata is a complex polygenic autoimmune disorder. Unknown environmental triggers signal an auto-inflammatory immune response that causes anagen phase hairs in the affected area to convert to telogen phase. Hair prematurely stops growing and sheds rapidly, causing patches of alopecia.

• Aetiology
  • Mostly unknown
  • There may be a specific trigger such as a febrile illness or severe emotional stress (for example, the death of a family member)
    • Less severe day-to-day stress is not considered to be a trigger
  • There is a strong family history component
• Clinical features
  • Discrete, often circular, areas of hair loss anywhere on the body
  • Patients typically present when hairloss in on the scalp, eyebrows or beard
  • 🍒A type of alopecia areata involving the entire scalp is called alopecia totalis
  • 🍒A type of alopecia areata involving the entire scalp and whole body is called alopecia universalis
  • 🍒Alopecia areata is characterised by unpredictable remission and relapse::timing
  • 🍒Peak incidence of alopecia areata is 20-30s
  • 🍒Characteristic exclamation point hairs may be observed in alopecia areata, particularly at the periphery of bald patches
• Prognosis
  • Poor prognostic indicators:
    • onset in childhood
    • extensive disease at initial presentation
    • ophiasis pattern (ie band-like alopecia involving the posterior scalp margin)
    • family history of alopecia areata or a predisposition to autoimmune conditions
    • history of atopy
    • nail changes (eg pits, roughening)
  • 🍒In alopecia areata, patients with a single patch of hair loss have a 80% chance of spontaneous complete regrowth within 12 months
• Management
  • 🍒What is the management of alopecia areata
• Sources:
  • eTG: Alopecia areata
  • Dermnet: Alopecia areata