Hair loss is a common problem that affects millions of men, women, and children. At least half of adults—both men and women—will experience some thinning or loss of hair by the time they are 60, and many men will become completely bald. This type of hair loss is different than the loss you experience every day when you shampoo or style your hair. The average person loses about 100 hairs a day. Abnormal hair loss means that you are shedding more than that and, in the case of the most common type of hair loss, the hair will not grow back. If you think your hair loss is excessive, or if you are losing patches of hair, you should see your doctor. He or she will be able to identify the cause and discuss your treatment options.
Hair loss may be temporary or permanent, and can have many causes. By far the most common type of hair loss is pattern baldness, also known as androgenetic alopecia. Men with pattern baldness initially lose hair in the front, crown, and sides of the hairline, and may become completely bald. Women are more likely to experience thinning at the crown and front of the head. This type of hair loss is hereditary, and is usually permanent. However, several treatments are available that may help regrow hair.
A type of hair loss called telogen effluvium typically occurs in response to stress on the body. This type of hair loss can be triggered by childbirth, major surgery, illness, severe psychological stress, and many other factors. Hair loss may not occur for three to six months after the stressful incident, so you may not make the connection between the two events. Fortunately, hair usually regrows within several months.
Alopecia areata is a temporary form of hair loss in which smooth, round patches of hair fall out from the scalp. This is a hereditary condition that can affect children or adults. There is no cure, but treatment sometimes helps.
Hair loss can also occur for many other reasons. In most cases other than pattern baldness, the hair will regrow.
There are many possible causes of hair loss.
- Heredity. Nearly all incidents of male and female pattern baldness (androgenetic alopecia) are due to family history.
- Major body stress. High fever, severe flu, surgery, and other stressful situations can cause hair loss, although it may not show up for weeks or months afterward.
- Childbirth. Some women experience hair loss several months after giving birth. The hair usually grows back.
- Medication side effect. A number of drugs can cause sudden hair loss. Certain medications used to treat arthritis, depression, heart problems, high blood pressure, and gout may have this effect.
- Medical treatment. Hair loss may result from cancer treatments such as chemotherapy or radiation therapy. Your hair will begin to regrow after you complete your treatment.
- Symptoms of a medical illness. Hair loss is a symptom of various conditions, such as thyroid disorders, diabetes, and lupus.
- Poor nutrition. You may have hair loss if your diet includes too little protein, iron, or other nutrients.
- Ringworm or tinea capitis (fungal infection of the scalp). In this type of infection, hair breaks off at the scalp, and the scalp becomes flaky or scaly.
- Alopecia areata. This disease of the immune system is often hereditary, but its cause is unclear.
- Hair treatments. Chemicals used to dye, bleach, straighten, or curl hair can cause damage if they are overused or used incorrectly. Heat from rollers or curling irons and hairstyles that pull hair tightly can also cause hair loss. This is known as traumatic alopecia.
- Trichotillomania. This is an abnormal desire to pull hair out.
Loss of 50, 100, or even more hairs each day is part of the normal hair growth cycle. If you notice unusually large amounts of hair in your sink or tub, in your hairbrush, on clothing, or on pillows, you may be experiencing abnormal hair loss. Other symptoms include thinning hair, a receding hairline, or bald patches.
The symptoms of pattern baldness (androgenetic alopecia) are different in men and women. In men, hair loss can begin any time after puberty, and is most likely to start for men in their twenties. In women, hair loss may also start at puberty, but typically is not apparent until at least 10 years later. In both men and women, the body's normal hair growth cycle gradually changes, and eventually hair in certain parts of the scalp stops growing entirely.
Hair loss follows a pattern Table 01. In men, the thinning begins at the temples and crown. Eventually, men become completely bald or have only a rim of hair along the side and back of the scalp. Women experience less severe hair loss. The hairline along the temple and forehead seldom recedes, as it does in men.
Table 1. Types of Hair Loss
Type of hair loss Symptoms Hereditary pattern baldness in men Thinning and loss start in the front, crown, and sides of the hairline Hereditary pattern baldness in women Thinning occurs in the front and crown Alopecia areata Loss of small round or oval patches of hair Telogen effluvium Loss of a considerable amount of hair in a short time, usually in response to a stressful situation, medication, medical treatment, or illness Trichotillomania The urge to pull hair from the scalp or other parts of the body
If you are losing hair because of a delayed reaction to stress, illness, hormonal change, or drug side effects, you are likely to experience hair loss all over the head. However, if your hair comes out in patches, you may have a tinea infection. Other signs of a fungal infection include scaling and crusting on the scalp and broken-off hairs.
Alopecia areata is marked by the loss of round or oval patches of hair. The bald patches usually appear suddenly. In severe cases, which are rare, hair loss may occur over the entire scalp or the entire body. This condition may occur only once or strike again at unpredictable intervals.
Trichotillomania is a mental health problem in which the main symptom is a compulsion to pull out hair, resulting in noticeable hair loss. Individuals with this disorder usually pull out scalp hair through frequent twisting and tugging, but may also pull their eyebrows, eyelashes, or hair on other parts of their body. Trichotillomania often begins in childhood or adolescence. Some experts believe it may be a way of attracting attention or a response to stress or tension.
Since pattern baldness is inherited, the strongest risk factor is having a parent who experienced hair loss or thinning. Heredity also influences the age at which hair loss begins, as well as the speed, pattern, and extent of the loss. While you cannot change your family history, you can try to slow hair loss by using FDA-approved treatments as soon as you notice symptoms.
Male and female pattern baldness is caused by a combination of genetics, hormones, and aging. Pattern hair loss affects an estimated 40 million men and 20 million women. About half of men will develop baldness by age 50, and about half of women will have some degree of hair loss or thinning by age 60.
Alopecia areata is also hereditary. However, you can develop this condition even if there is no history of it in your family. It can occur at any age, but is most likely to begin in childhood or the young adult years. Stress, seasonal factors, and infections may trigger alopecia areata. It is sometimes associated with autoimmune diseases such as rheumatoid arthritis, lupus, and early-onset diabetes.
Your risk for temporary hair loss is affected by many factors. Nutrition, certain drugs, medical treatments, stress, childbirth, and hair treatments are just a few of the things that can increase your risk for short-term hair loss.
Sharing combs, brushes, or hats with other people increases the risk that you will develop a fungal infection of the scalp.
When you see a doctor about hair loss, he or she will take your medical history and examine your hair and scalp. Your doctor will ask about hair loss or thinning in your relatives, which may indicate hereditary pattern baldness or another hereditary condition. The doctor will also want to know about your medications and diet, medical treatment, hair care habits, stress, and other aspects of your life that could cause hair loss.
The doctor will examine your scalp for signs of redness or scaling that may suggest an infection. The doctor may pull some hairs to see how easily they come out. This helps determine what proportion of your hair is growing and what proportion is resting. On average, about 90% of the hair is in a growth stage. Anything less than that percentage suggests a hair loss problem.
If the doctor suspects a fungal infection, a hair sample may be collected for laboratory testing. Blood tests will be needed if the doctor believes that an underlying medical condition such as a thyroid problem is causing the hair loss.
You may have a diagnosis other than pattern baldness if you have one or more of these symptoms:
- Your hair falls out suddenly or in clumps.
- You have patchy hair loss.
- You scalp is red or flaking in areas of hair loss.
- You have total loss of all body hair.
- You have a medical condition such as thyroid disease or were recently pregnant.
- You constantly pull, tug, or twist your hair until it breaks and falls out.
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