Health & Wellness

Understanding Hair Loss

Wendy Haaf answers your questions about health, nutrition, and well-being


Question: I’ve noticed that I’m shedding more hair than I normally do and the hair on my scalp seems to be thinning. What can I do to stop further loss and ideally grow some hair back?

Answer: “There are hundreds of reasons for losing hair, and many of the conditions look identical,” says Dr. Jeff Donovan, a Whistler, B.C., dermatologist who specializes in hair loss and is also a Canadian Dermatology Association spokesperson. “There are different treatments depending on the type of hair loss,” he says, so it’s important to determine the cause.

Excess shedding, known medically as telogen effluvium, is one of the most common types of hair loss. There are any number of root causes, many of which are either temporary or potentially reversible. Culprits include infections, weight loss, surgery, and stress, as well as some medications and medical issues that range from thyroid disorders and low iron to autoimmune diseases such as celiac. Typically, the hair loss happens about two months after the trigger, Donovan says, adding that there’s been an upswing in excess shedding over the past three years “because you can shed from COVID-19, even if you didn’t have symptoms.” In this case, the hair should grow back on its own.

Since some of these underlying conditions can cause other problems, Donovan recommends visiting your primary-care provider. “He or she can listen to your history, examine your scalp, and do blood tests to exclude common reasons like anemia,” he says. A careful history may also point to other possibilities. For instance, if autoimmune diseases run in your family and your iron levels are on the low side, it may be worth checking for celiac. Since some people don’t have obvious symptoms, “celiac can go undiagnosed for years,” Donovan says.

If no explanation is found and the hair loss persists, Donovan suggests seeing a specialist. Again, a careful history and scalp exam are key. “If you omit those two steps, you’re guessing,” he says.

The leading cause of lasting hair loss is an inherited condition called androgenetic alopecia—also known as male or female pattern baldness. Affecting up to 50 per cent of adults, it occurs when follicles—the structures that grow hair—overreact to sex hormones, producing hairs that are progressively shorter and thinner and then stopping entirely. “Females who have androgenetic hair loss often have a delay in diagnosis because it looks very different from such hair loss in men,” Donovan says. “Women lose hair in the centre of the scalp.”

After androgenetic hair loss and excess shedding, “the third most common reason for hair loss is things we do to our hair,” Donovan says. For instance, braids or ponytails that are too tight can lead to traction alopecia, while repeated bleaching or dyeing can result in hair breakage.

In alopecia areata, which affects an estimated one in 50 people, the immune system attacks hair follicles. The result can range from circular bald patches to complete hair loss.

More treatment options are available today than ever before. “As we learn more and more about these conditions,” Donovan says, “we’re getting better and better at treating them.”