We’ve all experienced hair loss in the shower, or while brushing or styling our hair. In fact, most people lose about 50-100 hairs each day, according to the American Academy of Dermatology (AAD). But if you’re losing more than that—perhaps you’ve noticed overall thinning, you have bald spots, or your shower shedding seems excessive—it could be due to one of a few common causes:
According to the AAD, approximately 80 million men and women in the U.S. experience hereditary hair loss, making it the most common cause. Referred to as female-pattern baldness or androgenetic alopecia, it typically occurs gradually and in the form of thinning hair or a widening part.
Significant hormonal changes and imbalances in your body can result in shedding locks, though it’s often temporary. Things like pregnancy, childbirth, and menopause are common culprits of hormonal hair loss. Some women, however, have fuller hair during pregnancy, when hormone levels are high, and experience excessive shedding after giving birth once the levels return to normal, according to WebMD. Birth control, which also alters your hormone levels, can also have an effect on your hair.
Excessive hair loss can be a sign of underlying medical conditions, such as thyroid disease, anemia, ringworm, or polycystic ovary syndrome (PCOS). The reasons for the loss varies based on the specific condition—from the existence of fungus with ringworm to iron deficiency with anemia—so the extent and treatment varies as well.
Some medications you take, whether prescription or over-the-counter, may be inadvertently responsible for your hair loss. Drugs used to treat cancer, depression, heart disease, arthritis, and blood pressure are all known to cause hair to fall out, according to the Mayo Clinic. Blood thinners, high doses of vitamin A, and anabolic steroids can also have that effect.
Diet and Nutrition
Significant weight loss, as well as eating disorders, can often result in increased shedding. As for your diet, a lack of protein or iron (as with anemia), or an excess of vitamin A might also be the cause.
Anything that causes you physical or emotional shock, from surgery to high fevers or severe psychological stress, can lead to as many as 70% of your scalp hairs to shed, according to the American Osteopathic College of Dermatology (AOCD). This is often referred to as telogen effluvium, and usually lasts for a couple months after the inciting event.
Hair Care or Styling
Harsh products, like bleach, dyes, or perm solutions can irritate and weaken your hair, especially when used regularly, according to the AAD. The same goes for excessive heat from blow dryers, straighteners, or curling irons. When your hair becomes brittle, it’s more likely to break and fall out. And any styles that pull your hair tightly (think: tight ponytails or cornrow braids) can irritate your scalp and lead to hair loss referred to as traction alopecia. Your hair is sensitive, so anything from too much washing and brushing to use of sharp or hard hairpins, is likely to irritate it.
If you’re concerned about your hair loss, make an appointment with a dermatologist to further investigate. Many of these causes are treatable or avoidable, but it’s important to first identify which are affecting you, with the help of a professional.