Hair Loss

Question 1

What are the four stages of the hair cycle?

Answer 1

1) Anagen/growing (85-90%)
2) Catagen/transition (1-3%)
3) Telogen/resting (10-15%)
4) Exogen/shedding (0.1%)

Question 2

What is androgenetic alopecia? What causes it? Symptoms?

Answer 2

Male-pattern baldness

• Due to DHT acting on hair follicles to promote premature hair loss via enzyme 5-alpha-reductase
• Women have fewer of these enzymes and DHT, therefore less hair loss
• Presents with symmetric, progressive hair loss that starts at the crown of the scalp with anterior hairline recession

Question 3

What is alopecia areata? What causes it? Symptoms?

Answer 3

• Auto-immune attack of T-lymphocytes against hair follicles, possibly due to stress, auto-immune disease
• Smooth, round, circular areas of complete hair loss (any hair bearing area, may itch/burn); can also have nail changes

Question 4

What is telogen effluvium? What can cause it? Symptoms?

Answer 4

• Abnormal number of hair follicles enter into telogen/resting phase prematurely, causing excessive shedding of hair
• Occurs 3-4 months after inciting trigger, which can include hormone changes in pregnancy, stress, infection, endocrine disorders, surgery, anemia, crash diets
• Can last for 6 months and may be generalized

Question 5

What is anagen effluvium? What causes it?

Answer 5

• Occurs due to toxicity that damages hair in anagen/growing phase
• Sudden and severe, fairly generalized
• Chemotherapy is a common causative agent

Question 6

What is scarring alopecia? What is the difference between primary and secondary scarring alopecia?

Answer 6

• Primary = Hair follicle is attacked and destroyed by autoimmune process
• Secondary = Hair follicles are bystanders in a destructive process; diffuse scarring in epidermis
• Require anti-inflammatory topical/systemic therapy and should be referred to physician if OTC products are not effective
• Can have pain, itch, irritation, scarring, atrophy, violaceous plaques