ALOPECIA

A continuación adjuntamos una revisión sobre la Alopecia y su relación con ciertos factores psicológicos, que será de utilidad para comentar el caso número 1. INTRODUCTION — Hair loss, or alopecia, is classified broadly as either scarring or nonscarring: Scarring alopecia refers to hair loss associated with fibrosis and scar tissue that replaces and often permanently destroys the hair follicle. Examples include bullous diseases, chemical alopecia, discoid lupus erythematosus, folliculitis (severe), lichen planopilaris, dissecting cellulitis, and tumors. Nonscarring alopecia refers to hair loss without permanent destruction of the hair follicle. Examples include anagen effluvium, androgenetic alopecia, chemical alopecia, folliculitis (mild), inherited disorders of the hair shaft, telogen effluvium, alopecia areata, and traumatic alopecia. All types of hair loss can be psychologically debilitating [1]. Thus, psychologic support is essential for all patients with hair loss. This review discusses the major nonscarring alopecias. Androgenetic alopecia and alopecia areata are discussed in detail separately. (See "Androgenetic alopecia" and "Alopecia areata".) HAIR GROWTH CYCLE — We have all of our terminal hair follicles at birth. Growth of each of these follicles on the scalp is cyclic [2]: The growth phase, termed anagen, lasts two to three years. The involutional phase, termed catagen, lasts two to three weeks. The resting phase, termed telogen, lasts three to four months. Hair is released from the hair shaft and shed at the end of telogen, and the next cycle is initiated. Telogen hairs are characterized by a mature root sheath, or "club," at the proximal end. In the normal scalp, approximately 80 to 90 percent of follicles are growing (anagen), about 5 to 10 percent are resting (telogen), and 1 to 3 percent are undergoing involution (catagen) [3,4]. Each day up to 75 hairs in telogen are shed from the scalp and about the same number of follicles enter anagen [2]. ANDROGENETIC ALOPECIA — Androgenetic alopecia is the most common type of hair loss, affecting approximately 30 to 40 percent of adult men and women [5]. The incidence is the same among men and women, although it may be camouflaged better in the latter. While it often affects women prior to the age of 40, the incidence increases around the time of menopause. Androgenetic alopecia is discussed separately. (See "Androgenetic alopecia".) ALOPECIA AREATA — Alopecia areata is a chronic inflammatory disorder affecting hair follicles and sometimes the nails that produces nonscarring hair loss. Patients typically develop discrete areas of complete hair loss. Alopecia areata is discussed separately. (See "Alopecia areata".) TELOGEN EFFLUVIUM — Telogen effluvium is the most common cause of diffuse hair loss. The disease results in reversible diffuse loss of mature, terminal hairs, usually following a significant stressful event (picture 1). Common triggers include pregnancy, severe weight loss (including with dieting), major illnesses and surgery, and traumatic psychological events. As mentioned above, normal hair loss averages 75 to 100 hairs per day. In telogen effluvium, rather than 1 to 5 percent of hair being lost in a staggered fashion, a stress triggers more hairs into the telogen phase, causing diffuse hair loss that peaks approximately three to four months after the inciting event. Usually up to 20 percent of the hair must be lost before it is cosmetically apparent. Thus, complaints of hair loss should not be discounted in someone who still has a full head of hair. Diagnosis — The "pull" test can be performed to document an active shedding process. Carefully grasp about two to three dozen hairs and lightly tug to see how many hairs will come out. Obtaining more than 5 telogen (club) hairs is abnormal. Patients can also perform daily counts of hair loss; as many as several hundred mature, telogen hairs may be lost each day. A history of an inciting event is helpful, but the absence of such an event does not rule out the diagnosis. Differential diagnosis Anagen effluvium — Anagen effluvium involves loss of growing (anagen) hair. Because the majority of hair is in this phase, acute loss involves 80 to 90 percent of hair. Anagen effluvium results from alkylating, antimitotic, or cytotoxic agents (eg, cancer chemotherapy) 10 to 14 days after the insult. (See "Chemotherapy-induced alopecia".) Androgenetic alopecia — As mentioned above, androgenetic alopecia involves gradual, not acute, loss of hair from the vertex or frontal hairline. In women the disease can be diffuse and difficult to distinguish clinically from telogen effluvium. Other — Other causes of diffuse hair loss should be considered if no inciting event can be identified. Many medications can cause hair loss (table 1) [6]. Additional conditions to consider include thyroid disease, connective tissue disease, hypervitaminosis A, syphilis, and nutritional deficiencies of zinc or biotin. It is uncertain whether iron deficiency and/or iron deficiency anemia cause hair loss [7,8]. Laboratory measurements that are usually appropriate in a patient with diffuse hair loss of uncertain etiology include: Thyroid stimulating hormone (TSH) Iron studies (serum iron and total iron binding capacity) In patients with historical risk factors for sexually transmitted diseases, testing for syphilis with an RPR is indicated. In patients with other evidence of an autoimmune disorder, testing for such disorders may include an antinuclear antigen (ANA). In women with diffuse hair loss and evidence of androgen excess (eg, acne, hirsutism, amenorrhea), testing should include total testosterone, dehydroepiandrosterone sulfate (DHEAS), and prolactin levels. (See "Androgenetic alopecia", section on 'Diagnosis'.) Treatment — There is no specific treatment for telogen effluvium. The first goal of therapy is to identify the cause. Review medications that the patient is taking and consider checking thyroid function tests, a serum ferritin, and CBC in unclear cases. Consider obtaining an ANA if the patient has systemic complaints suggestive of connective tissue disease. Patient education Patients with telogen effluvium should be reassured that they will not lose all of their hair, that the process is usually reversible, and that regrowth should occur over the next three to four months. Styling options (eg, permanents) may help existing hair look fuller and will not cause damage. Volumizing shampoos (readily available in grocery stores and pharmacies) may also help existing hair look fuller. TRAUMATIC ALOPECIA — Traumatic alopecia includes alopecia caused by mechanical traction, chemical trauma, and trichotillomania (nervous, self-induced hair pulling). Styling techniques that call for chronic tension on the hair, repeated use of lye-containing chemicals for hair straightening, or hot oils for styling may cause a reversible loss of hair that can become permanent if use of these techniques continues. In addition, habits of pulling, twisting, and plucking hairs cause a bizarre distribution of broken off hairs that is initially reversible but may become permanent if the habits persist. Clinical features — The distribution of hair loss varies depending upon styling techniques, but it is most prominent in areas where greatest tension occurs (picture 2). A bizarre, asymmetric, and irregular hair loss pattern is characteristic of trichotillomania (picture 3). Diagnosis — The diagnosis is made on the basis of the unusual pattern of hair loss. The history should include the exact styling techniques and products used. Occasionally a biopsy specimen is necessary to diagnose trichotillomania if the patient denies any hair-pulling habit. The hair pull test will show fragmented hairs of varying lengths. Differential diagnosis Alopecia areata — Hairs are not broken off at various lengths. There should be areas of smooth hair loss in round patches. Tinea capitis — Scaling is present. Look for adenopathy or erythema. KOH prep shows hyphae. (See "Dermatologic procedures", section on 'Potassium hydroxide prep'.) Treatment/patient education Decrease tension on hair roots by altering styling techniques, avoiding styling practices that require tension on the hair (eg, rollers, hot combing, braiding hair tightly). Avoid using harsh chemicals on the hair, especially those containing lye and hot oils for styling. Identify any habits or tics causing trichotillomania. Cognitive behavioral therapy usually is successful if the patient is recalcitrant to simple education [9]. (See "Psychological treatment of psychiatric disorders in primary care", section on 'Cognitive behavioral therapy'.) Fluoxetine hydrochloride (Prozac) 20 to 40 mg a day in adults or clomipramine (Anafranil) 25 to 250 mg/day in adults or a maximum of 3 mg/kg per day in children have had variable success for alleviating compulsive hair pulling [9-11]. Regrowth cannot be evaluated for several months. Hair loss may be permanent if the problem is longstanding. INFORMATION FOR PATIENTS — Educational materials on this topic are available for patients. (See "Patient information: Hair loss in men and women (androgenetic alopecia)" and "Patient information: Alopecia areata".) 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