The normal cycle of hair growth lasts for 2 to 3 years. Each hair grows approximately 1 centimeter per month during this phase. About 90% of the hair on your scalp is growing at any one time. About 10% of the hair on your scalp, at any one time, is in a resting phase. After 3 to 4 months, the resting hair falls out and new hair starts to grow in its place.
It is normal to shed some hair each day as part of this cycle. However, some people may experience excessive (more than normal) hair loss. Hair loss of this type can affect men, women, and children.
What is common baldness?
“Common baldness” usually means male-pattern baldness, or permanent-pattern baldness. It is also called androgenetic alopecia. Male-pattern baldness is the most common cause of hair loss in men. Men who have this type of hair loss usually have inherited the trait. Men who start losing their hair at an early age tend to develop more extensive baldness. In male-pattern baldness, hair loss typically results in a receding hairline and baldness on the top of the head.
Women may develop female-pattern baldness. In this form of hair loss, the hair can become thin over the entire scalp.
Symptoms of excessive hair loss
For most people, excessive hair loss is gradual, which means it happens over a long period of time. This is especially true of male-pattern baldness. Hair loss is considered excessive when it results in bald spots or hair that is noticeably thinning. In some cases, hair can fall out suddenly. This is typically caused by a sudden shock — either physical or emotional shock — to your body.
What causes excessive hair loss?
A number of things can cause excessive hair loss. For example, about 3 or 4 months after an illness or a major surgery, you may suddenly lose a large amount of hair. This hair loss is related to the stress of the illness and is temporary.
Hormonal problems may cause hair loss. If your thyroid gland is overactive or underactive, your hair may fall out. This hair loss usually can be helped by treating your thyroid disease. Hair loss may occur if male or female hormones, known as androgens and estrogens, are out of balance. Correcting the hormone imbalance may stop your hair loss.
Many women notice hair loss about 3 months after they’ve had a baby. This loss is also related to hormones. During pregnancy, high levels of certain hormones cause the body to keep hair that would normally fall out. When the hormones return to pre-pregnancy levels, that hair falls out and the normal cycle of growth and loss starts again.
Some medicines can cause hair loss. This type of hair loss improves when you stop taking the medicine. Medicines that can cause hair loss include blood thinners (also called anticoagulants); medicines used for gout, high blood pressure, or heart problems; vitamin A (if you take too much of it); birth control pills; and antidepressants.
Certain infections can cause hair loss. Fungal infections of the scalp can cause hair loss in adults and children. The infection is treated with antifungal medicines.
Finally, hair loss may occur as part of an underlying disease, such as lupus or diabetes. Since hair loss may be an early sign of a disease, it is important to find the cause so that it can be treated.
Can certain hairstyles or treatments cause hair loss?
Yes. If you wear pigtails or cornrows or use tight hair rollers, the pull on your hair can cause a type of hair loss called traction alopecia. If the pulling is stopped before scarring of the scalp develops, your hair will grow back normally. However, scarring can cause permanent hair loss. Hot oil hair treatments or chemicals used in permanents (also called “perms”) may cause inflammation (swelling) of the hair follicle. This can result in scarring and hair loss.
How is hair loss diagnosed?
If you suspect that you may have excessive hair loss, talk to your doctor. He or she will probably ask you some questions about your diet, any medicines you’re taking, and whether you’ve had a recent illness, and how you take care of your hair. If you’re a woman, your doctor may ask questions about your menstrual cycle, pregnancies, and menopause. Your doctor may want to do a physical exam to look for other causes of hair loss. Finally, your doctor may order blood tests or a biopsy (taking a small sample of cells to examine under a microscope).
Can hair loss be prevented or avoided?
There is no way to prevent male-pattern baldness (or female-pattern baldness) because it is a genetic trait, meaning you inherited a gene for baldness.
Some other causes of excessive hair loss can be prevented. For example, you could prevent hair loss by not styling hair too tightly in a way that puts too much pressure on your scalp. You also can talk to your doctor and avoid taking medications that could cause hair loss.
Depending on your type of hair loss, treatments are available. If a medicine is causing your hair loss, your doctor may be able to prescribe a different medicine. Recognizing and treating an infection may help stop the hair loss. Correcting a hormone imbalance may prevent further hair loss.
Medicines may also help slow or prevent the development of common baldness. One medicine, minoxidil (brand name: Rogaine), is available without a prescription. It is applied to the scalp. Both men and women can use it. Another medicine, finasteride, is available with a prescription. It comes in pills and is only for men. It may take up to 6 months before you can tell if one of these medicines is working.
Losing your hair can be devastating. Many people consider a thick head of hair a symbol of youth and vitality. So losing it — no matter how young you are — can make you feel old. It can make you feel less attractive. It can lower your overall self-esteem.
Remember that it is okay to feel what you’re feeling. It is also okay to seek out a strategy for stopping or even reversing hair loss. Wanting hair doesn’t mean that you are vain. You should not feel guilty about doing something about your hair loss.
If adequate treatment is not available for your type of hair loss, you may consider trying different hairstyles or wigs, hairpieces, hair weaves or artificial hair replacement.
Questions to ask your doctor
- What is causing my hair loss?
- Is there a treatment that will work for me?
- How long will it be before my hair grows back?
- Will my hair grow back the same, or will the texture be different?
- I have a fungal infection. How long will it take for the medicine to start working?
- Should I change my hairstyle?
- Can I do anything to make my hair look fuller?