Alopecia areata

Definition

Chronic inflammatory condition
affecting hair follicles causing
sudden onset non-scarring hair loss

Epidemiology

Pathophysiology

Clinical
presentation

Mechanism
Hair prematurely converted from growth (anagen)
phase to loss (telogen) phase, resulting in small hairs

Hair loss
Patchy, circular/oval areas, rarely total (totalis) or whole body (universalis)
Scalp, beard, eyebrows, eyelashes
May have nail changes
alopecia areata

Contributing factors
Genetics
Autoimmune reactions (T-cell mediated)
Stress
Neurogenic mechanisms

Common

Any age

M=F

Diagnosis

Differentials

Management

Complications

Psychological
Body image, self esteem, withdrawal
Anxiety, depression
School refusal, poor academic performance (children)

Prognosis

Unpredictable and variable

Spontaneous remission in
most people with limited loss <1y

Rare to progress from patchy disease
to total hair loss (alopecia totalis) ~1-5%

Poor prognostic factors
Childhood onset
Family history
Longstanding extensive alopecia
Scalp margin and nail involvement
Atopy or other autoimmune disease

Examination

Investigations

History

PMH
Mood disorder, autoimmune disease

DH
Current meds, allergies

PC/HPC
Hair loss: site (scalp, beard), sudden onset, patches/full
Associated symptoms (tingling, itch, burning): mood change

SH
Alopecia, baldness, autoimmune disease

SH
Occupation, living arrangements, support,
smoking, alcohol, diet

Dermatological examination
Rond patches/complete loss of scalp/beard hair
Underlying skin normal/slight erythema
Exclamation mark hairs (active disease)
Any hair regrowth (short, fine hairs)
Pull test (grasp small secton at periphery and pull to see
if they come loose; indicates active shedding)

Hand examination
Nail changes (putting, onchylosis, splitting,
longitudinal ridging, koilonychia, leukonychia)

Bedside
Obs

Bloods
Indication: diagnostic uncetainty
E.g. FBC, ferritin, TFTs

Biopsy
Indication: diagnostic uncetainty
Skin scrapings (fungal MCS)

Trauma
Tractional alopecia (hair styling, braids etc.)

Functional
Trichotillomania (pulling own hair out)

Infection
Tinea capitis
Shingles
Secondary syphilis

Endocrine
Androgenic alopecia

Autoimmune
Scarring alopecia (scleroderma, SLE, lichen planus)

Drugs
Anagen effluvium (chemotherapy, TCA, retinoids,
B-blockers, allopurinol, nitrofurantoin)

Conservative
Information, advice, support (NHS Choices, Alopecia UK)
Sun protection (hats, suncream)
Watchful waiting (evidence of hair growth or <50% loss)
Cosmetic options (hairstyling, camoflage, extensions, dermatography, false eyelashes, headscarves/hats, hairpieces, wigs)
Referral if no response to treatment, diagnostic uncertainty

Medical

Topical steroid
Indication: no hair regrowth and >50% involvement
E.g. topical betamethasone (lotion, foam, shampoo)
MOA: inhibits inflammation, allowing hair growth; can take >3m;
returns fine and depigmented first
NB. NOT for use on face (beard, eyebrows etc)

Steroid injections
Indication: specialist use

Topical immunotherapy
Indication: specialist use

Idiopathic
Telogen efflum (physical or psychological stress)

Metabolic
Deficiency (Zn, Fe)