Summary dermatology

Alopecia Areata

- Hair growth consists of 4 stages
o Anagen- growth phase
o Catagen- involution phase
o Telogen- resting phase
o Release- release of hair shaft
- Alopecia areata is a chronic relatpsing AI condition where anagen phase is
prematurely arrested
- Presumed AI condition causing localised, well demarcated patches of hair
loss
- At edge of hair loss there may be small, broken exclamation mark hairs
- It is a localised non-scarring alopecia
- Defined as
o Diffuse non-scarring
o Localised scarring
o Scarring
- Each category has a different cause
o Diffuse non-scarring- drug induced, metabolic
o Localised scarring- alopecia areata, trauma, ringworm
o Scarring- trauma (burns), lichen planus, discoid lupus

Causes
- Exact cause and mechanism is unknown
- AI condition can be triggered by trauma, stress or viral infection
- Those with first degree relative suffering with alopecia are more likely to be
affected

Symptoms
- Hair los may involve scalp, eyebrows, eyelashes or beard
- Circular regions of hair loss
- Non-scarring
- Exclamation mark hairs
- Nail changes-Beau’s lines, onycholysis and koilonychia

Investigations
- Clinical diagnosis
- Trichoscopy to examine hair and scalp

Complications
- Psychological- depression
- Increased risk of other AI conditions- DM and thyroid disease

Treatment

Conservative
- Patient educationa
- Assess extent of hari loss using scales such as Lugwig scale and Norwood
scale