7487 Week 4, Day 2 Alopecia Study Handout (NEWSOME)

Define alopecia.
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Define alopecia.
- partial or complete absence of hair from areas of the body where it normally grows
three layers of the hair shaft
- cuticle: outermost layer; responsible for elasticity and resiliency; determines general condition of the hair
- cortex: contains melanin and keratin; determines hair color and straight/curly texture, respectively
- medulla: innermost layer; supporting the structure of the hair
What constitutes the upper segment of the hair follicle?
- surface epidermis
- infundibular epidermis
- isthmus
- arrector pili muscle
What constitutes the lower segment of the hair follicle?
- stem
- bulb
three phases of hair growth
- anagen: growth phase; phase lasts around 1 month to 6 years depending on the type of hairs
- catagen: 1% to 3% of hair; transition phase; hair follicle starts to undergo apoptosis and reduces in size; lasts 2-3 weeks
- telogen: lasts 1-3 months; 10% to 15% of hair; the hair and the dermal papilla go into a resting phase; melanocytes go into apoptosis

**exogen phase is when the hair falls out
Describe the pathophysiology of hair growth.
- hormonal: androgens play a key role in pattern hair loss (specifically dihydrotestosterone or DHT shortens telogen phase)
- genetic association: genetic predisposition has been shown for alopecia areata (AA)
- hair cycle dynamics: in some cases, the anagen duration may significantly decline
- inflammation: chronic inflammation can lead to destruction of the hair follicle (irreversible)
- scarring: hair follicle replaced by fibrous tissue
Describe the clinical presentation of anagen hair loss (anagen effluvium).
- sudden onset
- short hair
- inability to grow longer
- empty follicles
- reversible (hair can regrow in 6 months)
Describe the clinical presentation of telogen hair loss (telogen effluvium).
- thinning hair
- sudden onset
- non-inflammatory alopecia
- lacking melanin
- loss of 300-500 hairs/day
Differentiate androgenetic alopecia (AGA) or male pattern hair loss, dermatologic disease, and scarring hair loss.
AGA:
- most common
- female patter preserves the frontal hairline

Dermatologic:
- may result in scarring or non-scarring patchy hair thinning and alopecia

Scarring:
- may be primary or secondary to indirect causes
Describe Alopecia Areata (AA).
- most frequent cause of inflammation-induced hair loss
- up to 66% of AA patients are younger than 30
- non-scarring
- autoimmune disease
- presents as acute, patchy alopecia
three most common causes of alopecia in children- tinea capitis - AA - telogen effluviumTreatment of alopecia should be......cause-specific.treatment approach for infectious alopecia- anti-infectives - tinea capitis requires systemic antifungal with oral terbinafine or itraconazoletreatment approach for chemotherapy-induced alopecia- generally reversible and temporary - non-pharmacotherapy is preferredtreatment approach for iron-deficiency alopecia- reversible - iron replacement therapy followed by iron supplementation is preferredtreatment approach for trichotillomania- non-pharmacologic and/or pharmacotherapy - CBT - SSRIs - olanzapine/clomipramine may also be effectivetreatment approach for male baldnessTopical Minoxidil: - main benefits seen may be prolongation of anagen phase - response should be assessed at 6 months Systemic 5 Alpha-Reductase Inhibitors - finasteride/dutasteride - finasteride recommended dose is 1 mg/day - dutasteride recommended dose is 0.5 mg/day - dutasteride has a long half-life and may have increased concentration with concomitant strong CYP3A4 inhibitors - both are teratogenicADRs of minoxidil- transient telogen hair shedding - hypertrichosis - contact dermatitisADRs of finasteride/dutasteride- orthostatic hypotension - dizziness - decreased libido - impotence - ejaculatory disordertreatment approach for female hair loss- topical minoxidil 2% is approved (not 5%; contraindicated in pregnancy/lactation) - topical/oral prostaglandin analog treatments may be promising (e.g., latanaprost, travoprost, and bimatoprost) - 5 alpha reductase inhibitors are contraindicated - spironolactone is the most commonly used off-label antiandrogen - flutamidetreatment approach for Alopecia Areata- curative therapy does not exist - intralesional corticosteroids (treatment of choice in adults; triamcinolone preferred) - topical corticosteroids (commonly used in children and adults with less than 50% scalp involvement) - systemic corticosteroids (ADRs limit their treatment periods to 2-3 months) - biologic agents: JAK inhibitors (tofacitinib, nixolitinib, baricitinib), IL-4 receptor antagonist (dupilumab) - azathioprine (used for alopecia universalis including recalcitrant cases in adults)