The differential diagnoses for hair loss are grouped into three categories: disturbances of the hair cycle, damage to the hair shaft, or disorders affecting the follicle. The following is not meant to be an exhaustive review of possible causes of hair loss, but instead common causes of hair loss in woman are highlighted.
Telogen effluvium: Normally the majority of scalp hair is in the growth phase, with a small percentage of hairs in the resting phase being shed daily (100-200 hair shed daily). Under certain circumstances a higher percentage of hairs cycle into the resting phase, and a woman may notice a sudden onset marked shedding. The exam usually reveals "normal" hair density and good scalp coverage on global exam, because more than 50% of the hair must be lost before hair loss is clinically apparent. If the patient is examined when the hair loss is still active, the pull test may be positive, otherwise hair regrowth with tapered ends may be seen. Common causes include high fever, childbirth, severe infections; severe "flu," severe chronic illness, major surgery, thyroid disorder, crash diets, inadequate protein, and certain drugs.
The shedding often starts months after the inciting cause but is always self-limited and reversible if the offending cause is corrected or resolved. Using the analogy that the hair cycle is much like a menstrual cycle may help the patient understand the biology of telogen effluvium. Furthermore reassuring her that the hair shaft and hair follicle are healthy and normal can give a positive focus to the visit.
Hair breakage: Hair is comprised primarily of the protein keratin, which is the same substance that forms fingernails and toenails. Sulfur crosslinks provide for the strength of the hair. Damage to the hair shaft by improper cosmetic techniques can cause hair breakage. There is little damage from normal dyeing, bleaching, waving or straightening. However, breakage can occur with too much tension during waving; waving solutions left on too long; or improperly neutralized, waving, and bleaching on the same day or too frequently. Other causes of hair breakage include excess tension in braids, ponytails, cornrows, or excess friction due to helmets or orthodontia. On examination, patchy areas of short hair with blunt (broken) hair tips can be seen. A tug of the distal hair shafts yields multiple short segments of hair.
Treatment of hair breakage usually requires alteration of the hair care routine. Hairstyles that pull on the hair, like ponytails and braids, should be put in as loosely as possible and should be alternated with looser hairstyles. If there is a constant pull on the hair, damage to the hair follicle can occur, resulting in traction alopecia, which is seen especially along the sides of the scalp. Shampooing, combing, and brushing too often can also damage hair, causing it to break. Recom mending a cream rinse, conditioner, or leave-in conditioner with silicone will make the hair more manageable and easier to comb. When hair is wet, it is more fragile, so vigorous rubbing with a towel, and rough combing and brushing should be avoided. Instead, the use of wide-toothed combs and brushes with smooth tips should be recommended. Also, using heat (blow-dryer, curling iron, flat iron) on wet hair can cause increased damage. Hair loss is reversible if the cosmetic procedure is stopped and the hair is handled gently; this is true even in early stages of traction alopecia. Stressing this reversibility should be the "take home message" for the office visit.
An drogenetic alopecia: Andro gen et ic alopecia or hereditary hair thinning is the most common form of hair loss in humans. This condition is also known as male-pattern hair loss or common baldness in men and as female-pattern hair thinning in women. Onset may occur in either sex at any time after puberty and the majority of thinning occurs in the teens, 20s, and 30s.
The cause of hereditary hair thinning is a gradual diminution of the hair follicle which occurs under the influence of androgens. The smaller hair follicle results in a finer and shorter hair shaft. Women with hereditary thinning usually first notice a gradual thinning of their hair, mostly on the top of their heads, and their scalp becomes more visible. Over time, the hair on the sides may also become thinner. The patient may notice that her "ponytail" is much smaller. This diffuse thinning of the scalp can vary in extent but it is extremely rare for a woman to become bare on top. Examination of the scalp will show a patterned hair loss with the frontal hairline intact but a widened central and sometimes temporal part compared to the occipital part. Miniaturized hairs are characteristic. Pull test is negative. Extensive laboratory tests are usually not needed if the woman with hereditary thinning has normal menses, pregnancies, and endocrine function. Thyroid disease and iron deficiency are two occult causes of hair thinning that can easily be ruled out by laboratory tests.
Treatment for women with hereditary thinning includes topical minoxidil solution, which when used regularly can partially re-enlarge the miniaturized hairs. In women, the use of 5% topical minoxidil applied twice daily was recently proven more efficacious than the previously recommended 2% minoxidil; however, there is a higher incidence of side effects with the stronger preparation such as scalp pruritus, local irritation, and unwanted hypertrichosis. Women with androgenetic alopecia may also consider spironolactone (inhibits androgen receptor binding) which has less evidence to back its efficacy, but might be a good choice in women with hypertension or women with hirsutism. Hair transplants are also an option in women, but cost issues may be prohibitive. Use of camouflage techniques should be encouraged in women with hereditary thinning including creative coiffures (tinting, waving, and teasing), and scalp covers (powders or creams).
Alopecia areata: Alopecia areata is an autoimmune disease that affects almost 2% of the population in the United States. In flammatory cells target the hair follicle, thus preventing hair growth. Typically a small round patch of hair is noticed; this patchy hair loss may regrow spontaneously. In other cases there can be extensive patchy hair loss and in rare cases there is loss of all scalp and body hair (alopecia areata universalis). Alopecia areata occurs equally in males and females, at all ages, although young persons are affected most often. Although the most common presentation of alopecia areata is patchy hair loss in scattered or oval patches, the hair loss can also involve the temporoccipital bane (ophiasis pattern hair loss). Brows, lashes, and body hair may also be involved. The nails may show track marks or pitting. On closer physical exam the areas of hair loss will reveal bare skin with retained follicular markings. The underlying scalp may have a slightly salmon-colored tint to it. A pull test is usually remarkably positive. Treatment for alopecia areata does not alter the natural course of the disease, nor does it prevent the formation of new patches of alopecia. The clinician must consider the extent of disease as well as the age of the patient when formulating a treatment regimen. Treatment options include one or a combination of the following: in tralesional corticosteroid, 5% topical minoxidil, short contact anthralin, topical steroid, topical immunotherapy, light treatment, and oral corticosteroids.
EmoticonEmoticon