What is Hair Loss?

by LiveScience Staff

Date: 28 September 2012 Time: 06:37 PM ET

Definition of Hair Loss: When a new hair fails to replace one that fell out of a follicle. In baldness, the thin hair that covers the entire body (vellus) replaces hair on the scalp. About 80 million people in the United States suffer from hereditary hair loss, according to the American Academy of Dermatology. Below is a brief overview of the causes, symptoms and treatments, plus links to more information.

What Causes Hair Loss? Hair loss has many causes. The most common is hereditary baldness, or androgenetic alopecia, which is driven by hormonal changes that can affect both women and men. Other common causes include:

Pregnancy
Thyroid problems
Anemia
Diabetes
Autoimmune disorders
Medications

Is Hair Loss Contagious?No. But some contagious scalp infections, such as ring worm, can lead to hair loss, according to the Mayo Clinic.

Medical Term: Alopecia

Signs & Symptoms: Depending on the cause, hair may thin, recede from a hairline, or come out in patches. It may fall out gradually or suddenly.

Treatment & Remedies: Minoxidil improves blood supply to follicles, and can somewhat improve baldness in men and women. The drug finasteride may stimulate hair growth in men. Other treatments for alopecia include corticosteroids, drugs that suppress the immune system and diet supplements. Hair may regrow by itself, depending on the cause. .

More Facts:

Up to 100 hairs fall out of the scalp every day in the normal cycle of hair growth.
A hair may grow for five years before resting, then falling out, according to the NIH.
There are about 120,000 hairs on a person's scalp.
About 95 percent of people with hair loss have hereditary baldness, according to the NIH.
The average person has about 5 million hairs on his or her body.

Sources and More Information:

This information is not meant to provide specific medical advice. It is for educational purposes only. We recommend you consult a qualified health care professional for diagnoses and treatment advice, and call 9-1-1 in emergencies.