Woman With Progressive Hair Loss

This 40-year-old woman complains of “hair loss,” although she has not noticed any unusual amounts of hair on her brush or comb or in the sink when she shampoos. She says that the problem has been slowly progressive for several years. She has not noticed any change in her scalp skin, and she denies a history of illness or joint pain in the preceding several years.

There is a family history of similar problems on her father’s side but not on her mother’s. During the past year, she has been on a low-carbohydrate diet and has lost 25 pounds.

On examination, there is definite though modest thinning of hair in a diffuse pattern over the crown of the scalp (A), along with preservation of the frontal hairline (B).
No surface disturbance of the scalp skin is noted.

What is the most likely explanation for this woman’s hair loss?

A. Lichen planus
B. Alopecia areata
C. Telogen effluvium
D. Androgenetic alopecia

(Answer on next page.)

Answer: D, Androgenetic alopecia

Androgenetic alopecia is caused by the effects of dihydrotestosterone (DHT) on genetically susceptible hair follicles. The occurrence of hair loss primarily in the crown scalp and the frontal hairline preservation in this patient’s case typify female-pattern androgenetic alopecia (Figure), although just as with male-pattern androgenetic alopecia, the clinical presentation can vary. And even though patients with androgenetic alopecia often complain of “hair loss,” there is no excessive amount of hair noted on brushes or combs or in the sink because what is actually happening is slow but progressive miniaturization of the hair follicle, essentially to the point of disappearance.

DIFFERENTIAL DIAGNOSIS

This contrasts quite sharply with the other choices, such as the next most common cause of alopecia in women, telogen effluvium (choice C), in which the hair loss affects the whole scalp uniformly, has a sudden onset, and involves observable lost hair. Thus, this choice is incorrect, even though the patient had been on a rather restricted diet, which is known to be a trigger for telogen effluvium.

Lichen planus (choice A)—or as it is called in the scalp, lichen planopilaris—involves patchy hair loss eventuating in permanent scarring alopecia by way of scaling, edema, and inflammation, none of which were present in this case. It is therefore an incorrect choice.

Alopecia areata (choice B) typically involves the acute onset of complete hair loss in round to oval patches, which can be single or multiple; may involve the periphery of the scalp (a phenomenon called ophiasis); and is usually self-limiting, although it can progress to total, permanent scalp hair loss (“alopecia totalis”) or even the loss of every hair in the body, termed alopecia universalis. Because it differs so radically from the presentation in this patient, it is an incorrect choice.

DIAGNOSIS

The diagnosis of androgenetic alopecia is usually clinical, but occasionally biopsy is necessary

TREATMENT

Currently, there is no effective treatment for androgenetic alopecia in women. Minoxidil solution is indicated for it, but the best outcome one could hope for with this medication is to slow the rate of loss. Finasteride, which has proved to be modestly effective for male androgenetic alopecia, is almost totally ineffective for the female version. Moreover, since it is a potent inhibitor of DHT, finasteride cannot be used by women with childbearing potential because of the risk of severe birth defects. Surgical implants are another option, just as with male androgenetic alopecia.

DISCUSSION

Androgenetic alopecia is, by far, the most common type of hair loss in both sexes and, with its familiar patterns, is usually easy to diagnose. But the combination of chronic androgenetic alopecia and acute telogen effluvium is also very common; the latter is often brought on by stress of various kinds, such as illness, surgery, weight loss, and changes in hormonal status (eg, those occurring postpartum and those associated with the use of oral contraceptives or estrogen replacement therapy). In patients who have scarring or patchy hair loss, the differential widens considerably, and more workup and/or referral is indicated, since causes can include such diverse entities as lupus and syphilis.