• Family history (heredity): The most common cause of hair loss is a hereditary condition that happens with aging. This condition is called androgenic alopecia, male-pattern baldness and female-pattern baldness.
• Hormonal changes and medical conditions: A variety of conditions can cause permanent or temporary hair loss, including hormonal changes due to pregnancy, childbirth, menopause and thyroid problems. Medical conditions include alopecia areata (al-o-PEE-she-uh ar-e-A-tuh), which is immune system related and causes patchy hair loss, scalp infections such as ringworm, and a hair-pulling disorder called trichotillomania (trik-o-til-o-MAY-nee-uh).
• Medications and supplements: Hair loss can be a side effect of certain drugs, such as those used for cancer, arthritis, depression, heart problems, gout and high blood pressure.
• Radiation therapy to the head: The hair may not grow back the same as it was before.
• A very stressful event: Many people experience a general thinning of hair several months after a physical or emotional shock. This type of hair loss is temporary.
• Hairstyles and treatments: Excessive hairstyling or hairstyles that pull your hair tight, such as pigtails or cornrows, can cause a type of hair loss called traction alopecia. Hot-oil hair treatments and permanents also can cause hair to fall out. If scarring occurs, hair loss could be permanent.
Courtesy: Mayo Clinic