Other disorders include alopecia areata, telogen effluvium, cicatricial alopecia, and traumatic alopecias.
The diagnosis is usually based on a thorough history and a focused physical examination.
A stepwise approach to the diagnosis of hair loss is provided in Adapted with permission from Healey PM, Jacobson EJ. With successive anagen cycles, the follicles become smaller (leading to shorter, finer hair), and nonpigmented vellus hairs replace pigmented terminal hairs.In women, the thinning is diffuse, but more marked in the frontal and parietal regions.Even persons with severe androgenetic alopecia almost always have a thin fringe of hair frontally.The remaining hair configuration may resemble a monk's haircut.A dropper is used to apply minoxidil solution directly onto dry scalp twice daily.
After each use, hands should be washed thoroughly to avoid inadvertent application to other parts of the body.
Approximately 60 hairs are grasped between the thumb and the index and middle fingers. A negative test (six or fewer hairs obtained) indicates normal shedding, whereas a positive test (more than six hairs obtained) indicates a process of active hair shedding. J Am Acad Dermatol 1996;35(3 pt 1):465–9Adapted with permission from Healey PM, Jacobson EJ. However, visible hair loss occurs in approximately one half of all persons by the age of 50 years8 Hair follicles contain androgen receptors.
Patients should not shampoo their hair 24 hours before the test is performed.4If the diagnosis is not clear based on the history and physical examination, selected laboratory tests and, occasionally, punch biopsy may be indicated. Philadelphia: Saunders, 208–11, with additional information from Drake LA, Dinehart SM, Farmer ER, Goltz RW, Graham GF, Hordinsky MK, et al. In the presence of androgens, genes that shorten the anagen phase are activated, and hair follicles shrink or become miniaturized.
Women with androgenetic alopecia do not have higher levels of circulating androgens.
However, they have been found to have higher levels of 5α-reductase (which converts testosterone to dihydrotestosterone), more androgen receptors, and lower levels of cytochrome P450 (which converts testosterone to estrogen).6Most women with androgenetic alopecia have normal menses, normal fertility, and normal endocrine function, including gender-appropriate levels of circulating androgens.
Therefore, an extensive hormonal work-up is unnecessary.