Evaluating and treating hair los (a...

Evaluating and treating hair los (alopecia) is an important part of primary care, nevertheless many physicians find it complicated and confusing. Hair loss affects men and women of all ages and commonly has significant social and psychologic ends This article reviews the physiology of normal hair produce common causes of hair los and treatments generally available for alopecia.

Normal Hair Growth

Each day the scalp hair extends approximately 0.35 mm (6 inches by means of year), while the scalp sheds approximately 100 hairs by day, and more with shampooing. (1) Because each follicle passes independently by means of the three stages of putting out the normal process of hair los usually is unnoticeable. At any united time, approximately 85 to 90 percent of scalp follicles are in the anagen phase of hair growing Follicles remain in this phase for an average of three years (range, couple to six years). (1) The transitional, or catagen, phase of follicular regression tread close upons usually affecting 2 to 3 percent of hair follicles. Finally, the telogen phase be met withs during which 10 to 15 percent of hair follicles experience a rest period for about three month At the conclusion of this phase, the inactive or dead hair is emited from the skin, leaving a solid, hard, white nodule at its proximal shaft. (2) The period is then repeated.

Evaluation of Hair Loss

A directed history and physical examination usually lay open the etiology of hair los The history should focus forward when the hair loss started; whether it was gradual or involved "handfuls" of hair; and if any physical, mental, or emotional stressors occurr within the previous three to six month (3) (Table 1) Determining whether the patient is complaining of hair thinning (i.e., gradually more scalp appears) or hair shedding (i.e., large quantities of hair falling out) may clarify the etiology of the hair los (4)

The pattern of hair los especially whether it is focal or diffuse, also may be helpful (Figure 1) The hair-pull exhibition gives a rough estimate of for what reason much hair is being missing (2,4) It is done on grasping a small portion of hair and gently applying traction while sliding the fingers along the hair shafts. Usually united to two hairs are remov with this technique. The hairs are then examined subordinate to a microscope (Table 2). In the hair-pluck example approximately 50 hairs are grasped with a hemostat and remov with undivided motion. (4) This test makes a trichogram to assess the telogen:anagen ratio if it were not that is rarely needed for clinical diagnosis of hair los Other diagnostic examples for alopecia also may be helpful (Table 2)

[FIGURE 1 OMITTED]

Androgenetic Alopecia

Androgenetic alopecia (AGA), or male-pattern baldness, is hair thinning in an "M"-shaped pattern; hair los arises on the temples and garland of the head with sparing of the sides and back (5) (Figure 2) This pattern cogitates the distribution of androgen-sensitive follicles in principally people. (6) Starting at puberty, androgens shorten the anagen phase and raise follicular miniaturization, leading to vellus-like hair formation and gradual hair thinning. (6)

Women also may experience AGA, frequently with thinning in the central and frontal scalp area nevertheless usually without frontal-temporal recession (Figure 3) A history and physical examination aimed at detecting conditions of hyperandrogenism, as it was as hirsutism, ovarian abnormalities, menstrual irregularities, acne, and infertility are indicated. Laboratory proofs are of little value in women with AGA who do not have characteristics of hyperandrogenism. (5)

Treatment options for AGA (Table 3) (6) focus forward decreasing androgen activity. Minoxidil (Rogaine) and finasteride (Propecia) are the simply medications approved by the U nutriment and Drug Administration (FDA) for the treatment of AGA (Figure 4) (6) Minoxidil is available without a prescription as a 2-percent topical solution that can be used from both men and women and as a 5-percent solution (Rogaine Extra Strength) that should be used by means of men only. The mechanism of action by dint of which minoxidil promotes hair growing is unknown, but it appears to act at the flat of the hair follicle. Minoxidil is an effective treatment for male and female AGA and is make acceptableed as first-line treatment by the American Academy of Dermatology guidelines. (5)

[FIGURE 4 OMITTED]

Minoxidil should be applied twice daily, and common year of use is commended before assessing its efficacy. (67) Women also may benefit from adjunctive treatments of that kind as estrogen (hormone replacement or oral contraceptives) or spironolactone (Aldactone). In men minoxidil may work better in areas with higher concentrations of miniaturized hairs, and its efficacy may be increased by dint of the synergistic use of once-daily tretinoin (Retin-A) applied at separate times during the day. (68) Minoxidil does not work upon completely bald areas and has relatively not many side effects; a dosage of 2 mL by day of a 2-percent solution costlinesss about $10.00 to $12.50 by month.

Finasteride inhibits 5a-reductase stamp 2, resulting in a significant decrease in dihydrotestosterone (DHT) flats (6) Studies have shown that, compared with placebo, 1 mg by day of finasteride slows hair los and increases hair product in men. (6,7,9) Dosages as gentle as 0.2 mg per day spring in decreased scalp and serum DHT flats in men, although the DHT flats may not correlate clinically with changes in hair los (10)