dermatologic disorders
Alopecia
Evaluation of Alopecia
History of present illnessshould cover the onset and duration of hair loss, whether hair shedding is increased, and whether hair loss is generalized or localized. Associated symptoms such as pruritus and scaling should be noted. Patients should be asked about typical hair care practices, including use of braids, rollers, and hair dryers, and whether they routinely pull or twist their hair. should include recent exposures to noxious stimuli (eg, drugs, toxins, radiation) and stressors (eg, surgery, chronic illness, fever, psychologic stressors). Symptoms of possible causes (eg, fatigue and cold intolerance [hypothyroidism] and, in women, hirsutism, deepening of the voice, and increased libido [virilization]) should be sought. Other features, including dramatic weight loss, dietary practices (including various restrictive diets), and Obsessive-Compulsive Disorder (OCD) , should be noted. In women, a hormonal/gynecologic/obstetric history should be obtained. should note known possible causes of hair loss, including endocrine and skin disorders. Current and recent drug use should be reviewed for offending agents (see table Some Causes of Alopecia ). A family history of hair loss should be recorded. Examination of the scalp should note the distribution of hair loss, the presence and characteristics of any skin lesions, and whether there is scarring. Part widths should be measured. Abnormalities of the hair shafts should be noted. A full skin examination should be done to evaluate hair loss elsewhere on the body (eg, eyebrows, eyelashes, arms, legs), rashes that may be associated with certain types of alopecia (eg, discoid lupus lesions, signs of secondary syphilis or of other bacterial or fungal infections), and signs of virilization in women (eg, hirsutism, acne, deepening voice, clitoromegaly). Signs of potential underlying systemic disorders should be sought, and a thyroid examination should be done. The following findings are of particular concern: Virilization in women Signs of systemic illness or constellations of nonspecific findings possibly indicating poisoning Hair loss that begins at the temples and/or crown (vertex) and spreads to diffuse thinning or nearly complete hair loss is typical of male-pattern hair loss. Hair thinning in the frontal, parietal, and crown regions is typical of female-pattern hair loss (see figure Male- and female-pattern hair loss (androgenetic alopecia) ). In androgenetic alopecia, the central part width is wider on the crown of the scalp than it is on the occipital scalp. Hair loss that occurs 2 to 4 weeks after Systemic Cancer Therapy or Other findings help suggest alternative diagnoses (see table Interpreting Physical Findings in Alopecia ). Anagen effluvium is a physiologic disruption of the anagen (growing) phase. It typically occurs several weeks after chemotherapy or radiation therapy. This photo shows an abrupt loss of hairs in the anagen phase along with sparse broken anagen hairs. © Springer Science+Business Media This photo shows typical acneiform lesions and deep keloidal scarring alopecia in a young male with acne keloidalis nuchae. © Springer Science+Business Media In this photo, the hair pulling is limited to the range of the person's right hand. © Springer Science+Business Media Other than hair loss, scalp symptoms (eg, itching, burning, tingling) are often absent and, when present, are not specific to any cause. Signs of hair loss in patterns other than those described above are nondiagnostic and may require microscopic hair examination or scalp biopsy for definitive diagnosis. Evaluation for causative disorders (eg, endocrinologic, autoimmune, toxic) should be done based on clinical suspicion. Male-pattern hair loss usually requires no testing. Female-pattern hair loss is usually evaluated with thyroid function testing. When it occurs in young men with no family history, the physician should question the patient about use of Anabolic Steroids and other drugs. In addition to questions regarding prescription drug and illicit drug use, women with significant hair loss and evidence of virilization should have levels of appropriate hormones (eg, Thepull testhelps evaluate diffuse scalp hair loss. Gentle traction is exerted on a bunch of hairs (about 40) on at least 3 different areas of the scalp, and the number of extracted hairs is then counted and examined microscopically. Normally,<3 telogen-phase hairs should come out with each pull. If > 4 to 6 hairs come out with each pull, the pull test is positive and is suggestive of telogen effluvium. Thepluck testinvolves sequentially pulling out about 50 individual hairs abruptly (“by the roots”). The roots of the plucked hairs are examined microscopically to determine the phase of growth and thus help diagnose a defect of telogen or anagen or an occult systemic disease. Anagen hairs have sheaths attached to their roots; telogen hairs have tiny bulbs without sheaths at their roots. Normally, 85 to 90% of hairs are in the anagen phase, about 10 to 15% are in telogen phase, and<1% are in catagen phase. Telogen effluvium shows an increased percentage of telogen-phase hairs on microscopic examination (typically > 20%), whereas anagen effluvium shows a decrease in telogen-phase hairs and an increased number of broken hairs. Primary hair shaft abnormalities are usually obvious on microscopic examination of the hair shaft. Scalp biopsyis indicated when alopecia persists and diagnosis is in doubt. Biopsy may differentiate scarring from nonscarring forms. Specimens should be taken from areas of active inflammation, ideally at the border of a bald patch. Fungal and bacterial cultures may be useful. Daily hair countscan be done by the patient to quantify hair loss when the pull test is negative. Hairs lost during the first morning combing or during washing are collected in clear plastic bags daily for 14 days. The number of hairs in each bag is then recorded. Scalp hair counts of>100/day are abnormal except after shampooing, when hair counts of up to 250 may be normal. Hairs may be brought in by the patient for microscopic examination. 