Hair Disorders

Question 1

Physiology of hair growth

Answer 1

Scalp:
small clusters of 3-4 hairs per follicle

Growth, 3 phases:

• ANAGEN, main growth period, 3-6years
• CATAGEN, slowing down or starting up, 2-3weeks
• TELOGEN; not currently growing, 3-4months

Follicle can move back and forth through this process based on hormones

When Anagen starts again the old hair is shed and new hair starts to grow.

92% of hairs are in Anagen at any time.

Normally lose about 50-100 hairs per day.

Signs of abnormal hair loss:

• hair on the pillow in the morning
• clogged drain after shower
• (hair stuck on brush is NOT a sign and is impossible to quantify)

Question 2

What is Telogen Effluvium?

Answer 2

• when a greater proportion of hairs enter telogen
• occurs after periods of stress (childbirth, blood loss, high fever major fractures)
• once hair loss is noted, patients are actually entering recovery stage as hair follicles enter anlagen stage (old hair shed, new one grows)
• can sometimes be chronic (hear falls out sooner eg after 4 years, men hair short so not seen, women notice hair gets thinner as its longer but thick at scalp)
• time will mostly resolve

Question 3

What is Anagen effluvium?

Answer 3

Always abnormal.
Can be caused by:
- inflammation
- infection
- radiation

Question 4

What is Alopecia Areata?

Types?

Answer 4

Autoimmune condition which starts with isolated patches of hair loss (one or more coin sized) on scalp and/or beard, eyebrows, eyelashes or body/pubic hair.

NKG2D+ T cells gather around hair follicles, attack and stop hair growth.

Types:

• alopecia areata (oval patces, can resolve or progress to totals or universalis)
• alopecia totalis (total loss of scalp hair)
• alopecia universalis (entire scale, face and body incl pubic hair)
• diffuse alopecia areata (aka incognita, rather than patches it is overall thinning, can look like telogen effluvium or baldness)
• alopecia areata ophiasis (pattern of sides and back of head hair loss, responds less to meds)
• alopecia barbae (patches or hair loss in beard or moustache)

Question 5

Management of alopecia areata?

Answer 5

• topical corticosteroids
• intralesional corticosteroid injection
• short term systemic corticosteroids
• topical immunotherapy; DCP (diphenylcyclopropenone) irritant / allergen that causes contact dermatitis and stimulates hair regrowth
• phototherapy PUVA
• laser
• dermatoscope will show exclamation mark hairs (thinning hair into root) and yellow dots (follicles without hair)

Question 6

Tell me about androgenic alopecia and its management?

Answer 6

aka male pattern baldness
(women loss hair at same rate but not in the same distribution)

FINASTERIDE is mainstay

• other anti-androgens have side effects
• 6-12months to notice improvement
• FHx of prostate cancer, be wary as finasteride made PSA unreliable

MINOXIDIL PO 0.5mg often with spironolactone
- can cause excess hair growth at other side eg arms and chest

MINOXIDIL TOPICAL

• 30% have moderate regrowth; 30%will slow hairs loss; 30% no effect
• moves follicles into anagen (but move out of anagen when med is stopped!)

Question 7

Management of female pattern hairloss?

Answer 7

• no cure
• topical minoxidil +/- tretinoin
• oral anti androgens (spironolactone)
• OCP
• finasteride not as effect in women

Question 8

What is trichotillomania?

Answer 8

• patient pulling out own hairs
• often unusual pattern of hair loss
• short hairs less than 1cm are hard to pull out so they remain

Question 9

What is tinea capitus?

Management?

Answer 9

• usually only seen in children, fairly acute onset
• fungal infection causing areas of hair loss, can be scaly

Management:

• antifungals: TERBINAFINE, ITRACONAZOLE, FLUCONAZOLE
• screen household and treat simultaneously