What is hair loss?
What is hair loss?
Hair growth typically completes a cycle in 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. The medical term for this is 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 sudden or prolonged stress, either physical or emotional.
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.