hair loss hair loss hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. typically at least the head is involved. the severity of hair loss can vary from a small area to the entire body. inflammation or scarring is not usually present. hair loss in some people causes psychological distress. hair lossother namesalopecia, baldnessa bald spot on a manpronunciationalopecia: /ˌæləˈpiːʃ(i)ə, -si.ə/ specialtydermatologysymptomsloss of hair from part of the head or body.complicationspsychological distresstypesmale-pattern hair loss, female-pattern hair loss, alopecia areata, telogen effluviumtreatmentaccepting the condition, medications, surgerymedicationpattern hair loss: minoxidil, finasteridealopecia areata: steroid injectionsfrequency50% of males, 25% of females (pattern hair loss by age 50) common types include male- or female-pattern hair loss, alopecia areata, and a thinning of hair known as telogen effluvium. the cause of male-pattern hair loss is a combination of genetics and male hormones; the cause of female pattern hair loss is unclear; the cause of alopecia areata is autoimmune; and the cause of telogen effluvium is typically a physically or psychologically stressful event. telogen effluvium is very common following pregnancy. less common causes of hair loss without inflammation or scarring include the pulling out of hair, certain medications including chemotherapy, hiv/aids, hypothyroidism, and malnutrition including iron deficiency. causes of hair loss that occurs with scarring or inflammation include fungal infection, lupus erythematosus, radiation therapy, and sarcoidosis. diagnosis of hair loss is partly based on the areas affected. treatment of pattern hair loss may simply involve accepting the condition, which can also include shaving one's head. interventions that can be tried include the medications minoxidil (or finasteride) and hair transplant surgery. alopecia areata may be treated by steroid injections in the affected area, but these need to be frequently repeated to be effective. hair loss is a common problem. pattern hair loss by age 50 affects about half of men and a quarter of women. about 2% of people develop alopecia areata at some point in time. terminology baldness is the partial or complete lack of hair growth, and part of the wider topic of "hair thinning". the degree and pattern of baldness varies, but its most common cause is androgenic hair loss, alopecia androgenetica, or alopecia seborrheica, with the last term primarily used in europe. hypotrichosis hypotrichosis is a condition of abnormal hair patterns, predominantly loss or reduction. it occurs, most frequently, by the growth of vellus hair in areas of the body that normally produce terminal hair. typically, the individual's hair growth is normal after birth, but shortly thereafter the hair is shed and replaced with sparse, abnormal hair growth. the new hair is typically fine, short and brittle, and may lack pigmentation. baldness may be present by the time the subject is 25 years old. signs and symptoms a case of mid-frontal baldness: andre agassi symptoms of hair loss include hair loss in patches usually in circular patterns, dandruff, skin lesions, and scarring. alopecia areata (mild – medium level) usually shows in unusual hair loss areas, e.g., eyebrows, backside of the head or above the ears, areas the male pattern baldness usually does not affect. in male-pattern hair loss, loss and thinning begin at the temples and the crown and hair either thins out or falls out. female-pattern hair loss occurs at the frontal and parietal. people have between 100,000 and 150,000 hairs on their head. the number of strands normally lost in a day varies but on average is 100. in order to maintain a normal volume, hair must be replaced at the same rate at which it is lost. the first signs of hair thinning that people will often notice are more hairs than usual left in the hairbrush after brushing or in the basin after shampooing. styling can also reveal areas of thinning, such as a wider parting or a thinning crown. throughout his political career, urho kekkonen, the president of finland, was well known for his baldness. he was last known to have had hair in about the 1920s. this photo is of kekkonen in 1959. skin conditions a substantially blemished face, back and limbs could point to cystic acne. the most severe form of the condition, cystic acne, arises from the same hormonal imbalances that cause hair loss and is associated with dihydrotestosterone production. psychological the psychology of hair thinning is a complex issue. hair is considered an essential part of overall identity: especially for women, for whom it often represents femininity and attractiveness. men typically associate a full head of hair with youth and vigor. people experiencing hair thinning often find themselves in a situation where their physical appearance is at odds with their own self-image and commonly worry that they appear older than they are or less attractive to others. psychological problems due to baldness, if present, are typically most severe at the onset of symptoms. hair loss induced by cancer chemotherapy has been reported to cause changes in self-concept and body image. body image does not return to the previous state after regrowth of hair for a majority of patients. in such cases, patients have difficulties expressing their feelings (alexithymia) and may be more prone to avoiding family conflicts. family therapy can help families to cope with these psychological problems if they arise. causes although not completely understood, hair loss can have many causes: pattern hair loss main article: pattern hair loss male pattern hair loss is believed to be due to a combination of genetics and the male hormone dihydrotestosterone. the cause in female pattern hair loss remains unclear. infection dissecting cellulitis of the scalp fungal infections (such as tinea capitis) folliculitis from various causes demodex folliculitis, caused by demodex folliculorum, a microscopic mite that feeds on the sebum produced by the sebaceous glands, denies hair essential nutrients and can cause thinning. demodex folliculorum is not present on every scalp and is more likely to live in an excessively oily scalp environment. secondary syphilis drugs temporary or permanent hair loss can be caused by several medications, including those for blood pressure problems, diabetes, heart disease and cholesterol. any that affect the body's hormone balance can have a pronounced effect: these include the contraceptive pill, hormone replacement therapy, steroids and acne medications. some treatments used to cure mycotic infections can cause massive hair loss. medications (side effects from drugs, including chemotherapy, anabolic steroids, and birth control pills) trauma traction alopecia is most commonly found in people with ponytails or cornrows who pull on their hair with excessive force. in addition, rigorous brushing and heat styling, rough scalp massage can damage the cuticle, the hard outer casing of the hair. this causes individual strands to become weak and break off, reducing overall hair volume. frictional alopecia is hair loss caused by rubbing of the hair or follicles, most infamously around the ankles of men from socks, where even if socks are no longer worn, the hair often will not grow back. trichotillomania is the loss of hair caused by compulsive pulling and bending of the hairs. onset of this disorder tends to begin around the onset of puberty and usually continues through adulthood. due to the constant extraction of the hair roots, permanent hair loss can occur. traumas such as childbirth, major surgery, poisoning, and severe stress may cause a hair loss condition known as telogen effluvium, in which a large number of hairs enter the resting phase at the same time, causing shedding and subsequent thinning. the condition also presents as a side effect of chemotherapy – while targeting dividing cancer cells, this treatment also affects hair's growth phase with the result that almost 90% of hairs fall out soon after chemotherapy starts. radiation to the scalp, as when radiotherapy is applied to the head for the treatment of certain cancers there, can cause baldness of the irradiated areas. pregnancy hair loss often follows childbirth in the postpartum period without causing baldness. in this situation, the hair is actually thicker during pregnancy owing to increased circulating oestrogens. approximately three months after giving birth (typically between 2 and 5 months), oestrogen levels drop and hair loss occurs, often particularly noticeably around the hairline and temple area. hair typically grows back normally and treatment is not indicated. a similar situation occurs in women taking the fertility-stimulating drug clomiphene. other causes autoimmune disease. alopecia areata is an autoimmune disorder also known as "spot baldness" that can result in hair loss ranging from just one location (alopecia areata monolocularis) to every hair on the entire body (alopecia areata universalis). although thought to be caused by hair follicles becoming dormant, what triggers alopecia areata is not known. in most cases the condition corrects itself, but it can also spread to the entire scalp (alopecia totalis) or to the entire body (alopecia universalis). skin diseases and cancer. localized or diffuse hair loss may also occur in cicatricial alopecia (lupus erythematosus, lichen plano pilaris, folliculitis decalvans, central centrifugal cicatricial alopecia, postmenopausal frontal fibrosing alopecia, etc.). tumours and skin outgrowths also induce localized baldness (sebaceous nevus, basal cell carcinoma, squamous cell carcinoma). hypothyroidism (an under-active thyroid) and the side effects of its related medications can cause hair loss, typically frontal, which is particularly associated with thinning of the outer third of the eyebrows (also seen with syphilis). hyperthyroidism (an over-active thyroid) can also cause hair loss, which is parietal rather than frontal. sebaceous cysts. temporary loss of hair can occur in areas where sebaceous cysts are present for considerable duration (normally one to several weeks). congenital triangular alopecia – it is a triangular, or oval in some cases, shaped patch of hair loss in the temple area of the scalp that occurs mostly in young children. the affected area mainly contains vellus hair follicles or no hair follicles at all, but it does not expand. its causes are unknown, and although it is a permanent condition, it does not have any other effect on the affected individuals. hair growth conditions. gradual thinning of hair with age is a natural condition known as involutional alopecia. this is caused by an increasing number of hair follicles switching from the growth, or anagen, phase into a resting phase, or telogen phase, so that remaining hairs become shorter and fewer in number. an unhealthy scalp environment can play a significant role in hair thinning by contributing to miniaturization or causing damage. obesity. obesity-induced stress, such as that induced by a high-fat diet (hfd), targets hair follicle stem cells (hfscs) to accelerate hair thinning in mice. it is likely that similar molecular mechanism play a role in human hair loss. other causes of hair loss include: alopecia mucinosa biotinidase deficiency chronic inflammation diabetes pseudopelade of brocq telogen effluvium tufted folliculitis genetics genetic forms of localized autosomal recessive hypotrichosis include: type omim gene locus lah1 607903 dsg4 18q12 lah2 604379 liph 3q27 lah3 611452 p2ry5 13q14.12-q14.2 pathophysiology hair follicle growth occurs in cycles. each cycle consists of a long growing phase (anagen), a short transitional phase (catagen) and a short resting phase (telogen). at the end of the resting phase, the hair falls out (exogen) and a new hair starts growing in the follicle, beginning the cycle again. normally, about 40 (0–78 in men) hairs reach the end of their resting phase each day and fall out. when more than 100 hairs fall out per day, clinical hair loss (telogen effluvium) may occur. a disruption of the growing phase causes abnormal loss of anagen hairs (anagen effluvium). diagnosis because they are not usually associated with an increased loss rate, male-pattern and female-pattern hair loss do not generally require testing. if hair loss occurs in a young man with no family history, drug use could be the cause. the pull test helps to evaluate diffuse scalp hair loss. gentle traction is exerted on a group of hairs (about 40–60) on three different areas of the scalp. the number of extracted hairs is counted and examined under a microscope. normally, fewer than three hairs per area should come out with each pull. if more than ten hairs are obtained, the pull test is considered positive. the pluck test is conducted by pulling hair out "by the roots". the root of the plucked hair is examined under a microscope to determine the phase of growth, and is used to diagnose