Merck Manual

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Some Causes and Features of Hair Loss

Some Causes and Features of Hair Loss


Common Features*


Hair loss over the entire scalp

Male-pattern hair loss (androgenetic alopecia)

Often a family history

Sometimes a history of using anabolic steroids

A doctor's examination

Female-pattern hair loss (androgenetic alopecia)

Often a family history

Sometimes occurring during menopause

Sometimes in women with masculine characteristics (virilization), a history of using anabolic steroids such as dihydrotestosterone, or a tumor that produces male hormones

A doctor's examination

Sometimes measurement of hormones: testosterone, DHEAS, FSH, and LH

Drugs and toxins

A history of using a specific drug such as certain chemotherapy drugs, anticoagulants, retinoids, oral contraceptives, ACE inhibitors, beta-blockers, lithium, antithyroid drugs, anticonvulsants, or high doses of vitamin A or of being exposed to metals such as thallium and arsenic

A doctor's examination

Sometimes blood tests to check for exposure to toxins or heavy metals

Stress (psychologic or physical) causing telogen effluvium

Severe psychologic stress

Recent weight loss, surgery, severe illness with a fever, or delivery of a baby

A doctor's examination

Sometimes blood tests to check for anemia and iron deficiency and to evaluate thyroid function

Thyroid disorders

With hyperthyroidism (an overactive thyroid gland), difficulty tolerating heat, sweating, weight loss, bulging eyes, shakiness (tremor), restlessness, and an enlarged thyroid gland (goiter)

With hypothyroidism (an underactive thyroid gland), difficulty tolerating cold, weight gain, coarse and thick skin, and sluggishness

A doctor's examination

Blood tests that evaluate thyroid function

Nutritional disorders, such as vitamin A excess or a deficiency of iron or zinc

Symptoms of the specific nutritional disorder

A doctor's examination

Sometimes blood tests to check for nutritional disorders

Typically patchy hair loss, but sometimes loss of all scalp hair (alopecia totalis); sometimes loss of all body and scalp hair (alopecia universalis)

A doctor’s examination†

Hair loss only in a specific area of the scalp

Alopecia areata

Round patches of hair loss with short broken hairs (resembling exclamation points) around the edges of the patches

Sometimes a burning sensation or itching

Sometimes loss of hair from the side and back edges of the scalp (ophiasis) or central hair loss, with sparing of the hairs at the margin of the scalp (sisaipho)

A doctor’s examination†

Cutaneous lupus erythematosus

Scattered patches of hair loss

Sometimes a rash on the scalp that tends to be red, raised, and scaly

Sometimes areas of scarring

Sometimes itching

A doctor's examination

Blood tests to check for lupus

Biopsy of the scalp

Central centrifugal cicatricial alopecia

Slowly progressive hair loss and scarring on the top and back of the scalp

Possibly caused by the use of hot combs, chemical relaxers, or hair weaves in people who have a genetic predisposition to develop this disorder

A doctor's examination

Biopsy of the scalp

Lichen planopilaris (lichen planus of the scalp) and frontal fibrosing alopecia

Related disorders that cause scattered patches of hair loss and scarring

Called frontal fibrosing alopecia when scarring hair loss occurs predominantly along the front of the hairline and the eyebrows

A doctor's examination

Biopsy of the scalp

Burns, injuries, or radiation (for example, from radiation therapy)

A history of burns, radiation therapy, or injury

Often scarring

A doctor's examination

Sometimes other tests to check for the cause

Tinea capitis (ringworm of the scalp)

Bald areas sometimes with small black dots (due to hair that has broken off at the scalp surface) or hairs broken just above the scalp surface

Round, scaly areas of skin, which can be red or inflamed

A doctor's examination†

Examination of plucked hairs under a microscope and/or culture of plucked hairs

Traction alopecia

Braids, rollers, or ponytails that are left in too long or pulled too tight

A doctor's examination†

Trichotillomania (compulsive hair pulling)

Typically an asymmetric, bizarre, irregular hair loss pattern

Sometimes obsessive-compulsive behavior

Affects women 4 times more often than men

A doctor's examination†

* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present.

† Rarely, biopsy of the scalp is done.

ACE = angiotensin-converting enzyme; DHEAS = dehydroepiandrosterone sulfate; FSH = follicle-stimulating hormone; LH = luteinizing hormone; PCOS = polycystic ovary syndrome.