Alopecia - Block 1 Flashcards
What are the 3 layers of hair?
- Cuticle
- Cortex
- Medulla
What are the phases of hair growth?
- Anagen (growth phase)
- Catagen (transition phase)
- Telogen (resting phase and apoptosis)
- Exogen (hair falls out)
What is the length of anagen phase?
Short hair: 1 month
Long hair: 6 yrs
How long is the catagen phase?
2-3 weeks
How long is the telogen phase?
1-3 months
What is the hormone that contributes to hair loss?
dihydrotestosterone
What is the function of 5a reductase?
Testosterone is converted to DHT by 5a reductase
What is an drug class that may help with male and female pattern hair loss?
5a reductase inhibitors
How is alopecia linked to genetics?
Linked to variants of androgen receptor locus on X chromosomes
Prevalence of genetic alopecia?
Higher incidence among affected males and maternal grandfathers
What is anagen hair loss?
Anagen effluvium: sudden onset where hair appears thin but not fragile
* reversible with hair regrowth within 6 months
What are some causes of anagen hair loss?
Autoimmune dx: Diffuse, rapid hair shedding with “exclamation mark” hairs
Chemo: Recovery usually occurs within 6 months of therapy completion
Inherited/congenital
What is telogen hair loss?
Telogen effluvioum: non inflammatory with sudden onset
* Observed 3 months after med condition that stops hair growth
* Hair regrowth can occur after 4 months after withdrawal of medication-induced causes.
What are causes of telogen hair loss?
- Pregnancy
- Stress
- Infection
- Weight loss
- Autoimmune dx
- THD
- Vitamin def
- Meds
What are medications that can induce alopecia?
Anti-arrhythmic Agents
ACE Inhibitors (ACE-Is)
Angiotensin-II Receptor Blockers (ARBs)
Anticonvulsants
Anticoagulants
Antidepressants
Antipsychotics
Beta-Blockers
Contraceptive Agents
Hormonal Agents
Immunosuppressants
Stimulant Agents
Thyroid Agents
Xanthine Oxidase Inhibitors
Vitamin A Analogs
Oncology Agents
What are the most common hair loss in adult males? Why?
Androgenic alopecia due to DHT effect
Can women get androgenetic alopecia?
Yes, due to excessive androgen levels presented as thinning hair on the mid frontal area (PCOS)
What is alopecia areata?
Inflammation induced hair loss due to the presence of hair-follicle specific autoantibodies and exclammation mark hairs
What are the diagnosis of hair loss?
- Hair tug and pull test
- PMH of medications
- Suspected iron deficiency anemia (CBC, TIBC, ferritin, TSAT)
- Female patients with alopecia (DHEA, testosterone)
- Suspected chemotherapy-induced alopecia
- Suspected case of trichotillomania (hair pulling disorder)
- Suspected other systemic autoimmune conditions
* SLE (i.e., ANA, ESR, CRP, autoantibodies)
* Hypothyroidism or hyperthyroidism (i.e., TSH)
What is a positive hair tug test?
Positive (+) tug test = >10% of hairs fracture
What is the outcomes of a hair pull test?
Likely to extract more hairs in telogen phase than anagen phase:
Telogen hair -> “club-shaped”
Anagen hair -> “long sheath-shaped”
What are the non pharm of hair loss?
- Not appropriate to brush hair (>100 strokes/day) or massage scalp vigourously
- Patients with alopecia should comb or brush their hair ONLY when dry
What is the pharm tx for male pattern baldness?
- Topical minoxidil
* 2% and 5% topical colution
* 5% topical foam - PO 5a reductase inhibitors
Topical Minoxidil
Brand, Warning, Counseling
Rogaine
Warning: Pregnancy and lactation
* Use only on scalp, avoid contact with eyes, mouth, nose
Counseling:
* Administer to hair loss areas on the scalp ONLY
* Administer medication at least 2 hours before bedtime to reduce risk of contaminating bedding materials
