Your doctor will ask you some questions about your hair loss and past health. He or she will also do a physical exam. Your doctor will look closely at your scalp and hair loss pattern. He or she may gently tug on a few hairs or pull some out for tests.

The most common cause of hair loss—inherited hair loss—is easy to recognize. Men tend to lose hair from the forehead area and top of the head but have normal amounts of hair on other areas of the scalp. Women tend to keep their front hairline but have thinning of the hair on the top of the head.

Hair loss history

To find the cause of your hair loss, your doctor may ask you about:

• Characteristics of your hair loss. Is your hair thinning, with your scalp becoming more visible, but your hair isn't noticeably falling out? Or is your hair shedding, with lots of hair falling out?
• How long your hair loss has been occurring. How long has it been since you had your normal amount of hair?
• Your family history of hair loss. Does your mother or father, brother or sister, or any other relative have hair loss? If so, what caused their hair loss?
• Your hairstyling habits. Has your hair become fragile from pulling it too tight or from other hairstyling habits? Have you had any chemical treatments to your hair, such as permanents (perms) or bleaching? Do you use a blow-dryer that may be too hot? Is a curling iron damaging your hair?
• Any recent illness. Have you had any skin rashes, such as ringworm, recently?
• Medicines you take. Are you taking blood thinners (anticoagulants) or medicines for arthritis, depression, or heart problems? Have you had any cancer treatment?
• Your diet. Are you getting enough protein and iron in your diet?

Tests

If the reason for your hair loss isn't clear, your doctor may do tests to check for a disease that may be causing your hair loss. Tests include:

• Hair analysis. Your doctor will take a sample of your hair and examine it under a microscope. A scalp sample might also be taken.
• Blood tests. These may include tests for a specific condition, such as an overactive or underactive thyroid gland (hyperthyroidism or hypothyroidism).

Hair loss in women

Hair loss in women is harder to diagnose than it is in men. That's because the pattern of hair loss isn't as noticeable as it is in men.

Testing to diagnose hair loss usually isn't done in women with mild to moderate hair thinning who are otherwise healthy. But in women who have irregular menstrual cycles, continued episodes of acne, or too much body hair (hirsutism), testing for a class of hormones called androgens, including testosterone, is sometimes done.