Hair loss can appear in many different ways, depending on the problem that's causing it. It can come on suddenly or gradually and affect just your scalp or your whole body. Some types of hair loss are temporary, while others are permanent.
Signs and symptoms of hair loss may include:
- Gradual thinning on top of head. This is the most common type of hair loss, affecting both men and women. In men, hair often begins to recede from the forehead in a line that resembles the letter M. Women typically retain a line of hair at the forehead but experience a broadening of the part in their hair.
- Circular or patchy bald spots. Some people experience smooth bald spots, often about an inch (2.6 centimeters) across. This type of hair loss usually affects just the scalp, but it sometimes also occurs in beards or eyebrows. In some cases, your skin may become itchy or painful before the hair falls out.
- Sudden loosening of hair. A physical or emotional shock can cause hair to loosen. Handfuls of hair may come out when combing or washing your hair or even after gentle tugging. This type of hair loss usually causes overall hair thinning and not bald patches.
- Full-body hair loss. Some conditions and medical treatments, such as chemotherapy for cancer, can result in the loss of hair all over your body. The hair usually grows back after treatment ends.
When to see a doctor
Talk to your doctor if you notice sudden or patchy hair loss or more than usual hair loss when combing or washing your hair. Sudden hair loss can signal an underlying medical condition and may require medical treatment.
Most people normally shed 50 to 100 hairs a day. But with about 100,000 hairs in the scalp, this amount of hair loss shouldn't cause noticeable thinning of the scalp hair. As people age, hair tends to gradually thin. Other causes of hair loss include hormonal factors, medical conditions and medications.
The most common cause of hair loss is a hereditary condition called male-pattern baldness or female-pattern baldness. In genetically susceptible people, certain sex hormones trigger a particular pattern of permanent hair loss. Most common in men, this type of hair thinning can begin as early as puberty.
Hormonal changes and imbalances can also cause temporary hair loss. This could be due to pregnancy, childbirth, discontinuation of birth control pills or the onset of menopause.
A variety of medical conditions can cause hair loss, including:
- Thyroid problems. The thyroid gland helps regulate hormone levels in your body. If the gland isn't working properly, hair loss may result.
- Alopecia areata. This disease occurs when the body's immune system attacks hair follicles — causing smooth, roundish patches of hair loss.
- Scalp infections. Infections, suchasringworm, can invade the hair and skin of your scalp, leading to hair loss. Once infections are treated, hair generally grows back.
- Other skin disorders. Diseases that can cause scarring, such as lichen planus and some types of lupus, can result in permanent hair loss where the scars occur.
Hair loss can be caused by drugs used to treat:
- Heart problems
- High blood pressure
Other causes of hair loss
Hair loss can also result from:
- A physical or emotional shock. Many people experience a general thinning of hair several months after a physical or emotional shock. Examples include sudden or excessive weight loss, a high fever, or a death in the family.
- Hair-pulling disorder. This mental illness causes people to have an irresistible urge to pull out their hair, whether it's from the scalp, their eyebrows or other areas of the body. Hair pulling from the scalp often leaves patchy bald spots on the head.
- Certain hairstyles. Traction hair loss can occur if the hair is pulled too tightly into hairstyles such as pigtails or cornrows.