skin disorders
Alopecia (Hair Loss)
Causes of Alopecia
Themost common causeof hair loss is Male-pattern and female-pattern baldness ( Androgenetic alopecia ) Other common causesof hair loss are Alopecia Areata None Certain systemic disorders, such as Cutaneous lupus erythematosus and hormonal disorders Drugs, particularly chemotherapy Fungal infections, such as ringworm of the scalp ( Scalp Ringworm (Tinea Capitis) ) Physical stresses such as a high fever, surgery, a major illness, sudden weight loss, or pregnancy (all of which can lead to a telogen effluvium) Psychologic stresses Injury (trauma) Injury to the hair follicles has many causes including Hair-Pulling Disorder (Trichotillomania) (habitual pulling out of normal hair related to psychologic stresses) Traction alopecia (hair loss caused by continuous traction such as from braids, rollers, or ponytails) Burns and radiation Pressure-induced hair loss (for example, after an operation where prolonged pressure on the scalp caused damage to hair follicles) Central centrifugal cicatricial alopecia causes hair loss with scarring beginning at the top of the scalp. Causes are multifactorial. Less common causesinclude primary hair shaft abnormalities (that is, the abnormality originates in the hair shaft), lichen planopilaris (lichen planus of the scalp) and frontal fibrosing alopecia, , and rare skin conditions. About 50 to 100 scalp hairs normally fall out each day. This form of alopecia increases with age and affects over 70% of men (male-pattern hair loss) and 57% of women (female-pattern hair loss) over the age of 80. The hormone dihydrotestosterone plays a major role, along with heredity. The hair loss can begin at any age during or after puberty, even during adolescence (see figure Losing Hair ). Androgenetic alopecia is more common among White people than among Asian and Black people. In men, hair loss usually begins at the temples or on the top of the head toward the back. Some men lose only some hair and have only a receding hairline or a small bald spot in the back. Other men, especially when hair loss begins at a young age, lose all of the hair on the top of the head but retain hair on the sides and back of the scalp. This pattern is called male-pattern hair loss. In women, hair loss occurs on the top of the head and is usually a thinning of the hair rather than a complete loss of hair. The hairline typically stays intact. This pattern is called female-pattern hair loss. In men, hair is usually first lost at the temples or on the top of the head toward the back. This pattern is called male-pattern hair loss. In women, hair is usually first lost on the top of the head. Typically, the hair thins rather than is completely lost, and the hairline stays intact. This pattern is called female-pattern hair loss. In Alopecia Areata , typically round, irregular patches of hair are suddenly lost. More extensive loss of scalp and body hair can also occur. This disorder is believed to be caused by a malfunction of the body's immune system that causes the body to attack its own tissues (called an autoimmune reaction). Central centrifugal cicatricial alopecia is the most common cause of scarring alopecia in Black women. The combination of damage to the scalp, possibly resulting from hot combs, chemical relaxers, or hair weaves, and a genetic predisposition to follicular damage due to abnormal hair follicles leads to progressive hair loss and scarring on the top and back of the scalp. In cutaneous lupus erythematosus, areas of hair may be lost. Hair loss may be permanent if the hair follicle is completely destroyed. Cutaneous lupus erythematosus can affect people who have or do not have Systemic Lupus Erythematosus (SLE) (SLE, or simply lupus), a disorder in which antibodies or cells produced by the body attack the body's own tissues (called an autoimmune disorder). Systemic lupus erythematosus affects various organs throughout the body and can cause widespread nonscarring hair loss. In cutaneous lupus erythematosus, hair tends to be lost in patches and scarring or permanent hair loss can occur. If women have excessive amounts of male hormones or are more sensitive to the effects of male hormones (for example, genetically), they can develop scalp hair loss, Acne , and hair growth in locations more typical of male hair growth, such as the face and trunk ( Male-pattern or female-pattern baldness can occur when anabolic steroids are used. Chemotherapy drugs typically cause disruption of the growing phase that causes loss of anagen hairs (anagen effluvium). Other prescription drugs (for example, blood thinners and drugs used to treat high blood pressure, acne, thyroid disorders, or seizures) typically cause hair loss by inducing a telogen effluvium. Nutritional disorders are a less common cause of hair loss. Symptoms vary according to the specific nutritional disorder: Vitamin A Excess : Rash, scaly chapped lips, painful swelling of the limbs, sluggishness, loss of appetite, and weight loss Iron Deficiency : Anemia, easy exhaustion, and a decreased ability to exercise Zinc Deficiency : Rash, diarrhea, frequent infections, loss of appetite, and poor wound healing Stresses such as a high fever, surgery, a major illness, weight loss, or pregnancy can increase the number of hairs that go into the resting phase (causing telogen effluvium). Hair typically falls out a few months after the stress. This type of hair loss tends not to be permanent. These stresses can lead to the habitual twisting, teasing, or pulling out of normal hair ( Hair-Pulling Disorder (Trichotillomania) ). The habit is most common among children but may occur in adults. The hair pulling may not be noticed for a long time, confusing doctors and parents, who may mistakenly think that a disorder such as Scalp Ringworm (Tinea Capitis) is a fungal infection that is a common cause of patchy hair loss in children. The infection begins as a dry, scaly patch that gradually enlarges. Hairs may eventually break off, usually flush with the surface of the scalp, looking like black dots. Sometimes the hair breaks off above the surface of the scalp, leaving short stubs. Hair loss may be permanent, especially if the infection is left untreated. This disorder is hair loss caused by tight braids, rollers, or ponytails that pull constantly on hair. Hair loss most often occurs at the hairline of the forehead and temples. 