Hair Loss (Androgenic Alopecia) Flashcards
In androgenic alopecia terminal hair follicles transform into more vellus-like hair follicles as a result of preferential binding by what?
Dihydrotestosterone (produced from the conversion of androgen by 5-alpha reductase) to hair follicle receptors. Eventually the hair follicle ceases activity completely with resulting hair loss.
What are the clinical features of androgenic hair loss in men?
Initially a thinning of the hair and a frontal receding hairline that might or might not be accompanied with hair loss at the crown.
What are the clinical features of androgenic hair loss in women?
The frontal hairline is maintained with diffuse hair loss that is somewhat accentuated at the crown.
What happens to hair during pregnancy?
Circulating levels of oestrogen increase, resulting in the number of follicles in anagen (growth phase); the hair therefore thickens.
After pregnancy, the hair then returns to its normal appearance with some thinning etc occuring.
Is androgenic hair loss associated with other symptoms?
No. If itch and/or erythema are present then this indicates another cause e.g. fungal infection, psoriasis or seborrhoeic dermatitis.
What patterns of hair loss inidicate referral?
Men: hair loss normally occurs at the front of the head and recedes backwards or at the crown.
Women: hair loss tends to be generalised and diffuse.
Presentations that differ to this or are sudden in onset suggest another cause of hair loss.
What endocrine disorder is most commonly associated with hair loss?
Thyroid conditions.
Hypothryoid and diabete mellitus.
Iron deficiency is associated with what type of hair loss?
Femal hair loss. If this is the cause, a 2-month course of iron supplementation should result in thickening of the hair. If the patient fails to respond to treatment then the patient should be reassessed.
What is alopecia areata?
Hair loss of unknown origin, although there is often an association with atopy and autoimmune disease and a positive family history is found in up to 25% of patients.
It is relatively uncommon affecting 0.1 to 0.2% of the UK population.
Usually self-limiting and regrowth of hair is often observed but repeated episodes are not unusual.
What is traction alopecia?
Refers to hair loss due to excess and sustained tension on the hair.
Retinoids can cause hair loss in what % of patients?
20% approx
Can colchicine and carbimazole cause hair loss?
Rarely
Lithium carbonate can cause hair loss in what % of patients?
10% approximately
Hair loss can be seen in those who stop taking oral contraceptives how long after stopping treatment?
2-3 months
What products are available for androgenic alopecia?
Minoxidil topical 2 or 5% lotion and oral finasteride.
