Understanding Seasonal Hair Loss: When It’s Normal and When to See a Dermatologist

Finding more hair in your brush or shower drain can feel unnerving, especially if it seems to happen like clockwork each year. But seasonal hair shedding is a natural part of the hair cycle, and it’s normal for both men and women to shed between 50 and 100 hairs a day.

“Practically, it’s likelier to be noticed if you have more hair, as women often do,” says Ranella Hirsch, MD, a board-certified dermatologist based in Cambridge, Massachusetts.

Fortunately, most cases of this type of hair loss are temporary and nothing to be overly concerned about. People with seasonal hair loss rarely feel their overall hair volume is thinning, says Mary Lupo, MD, a board-certified dermatologist and the founder of the Lupo Center for Aesthetic and General Dermatology in New Orleans.

Is Seasonal Hair Loss Real?

Seasonal shedding is a thing, but it’s not clearly understood. Shifts in seasons can temporarily slow or halt hair growth, which can result in a detectable increase in shedding soon after.

An older study of 823 women found that hair shedding peaks in summer; a second, less pronounced peak happens in spring; and hair shedding is least pronounced in the wintertime.

A more recent study, based on eight English-speaking countries’ Google search data from January 2004 to October 2016, found that summer and autumn were associated with more searches for the term “hair loss,” suggesting that those seasons were when more people experienced hair loss.

More research is needed to fully understand the reasons behind these results. Some evolutionary theories about seasonal hair loss are also in play. “Anthropologically, there was an advantage for hair to be thickest in winter for protection from cold,” says Dr. Lupo. “To get an increase in new hair, you must shed the existing hair.” This process is known as the hair growth cycle.

The Hair Growth Cycle

“Hair growth exists in cycles,” says Dr. Hirsch, which includes normal shedding. The hair growth cycle is broken down into four stages:

• Anagen: This represents the active growth phase, when hair comes out of the follicle, lasting anywhere from two to eight years.
• Catagen: During this two- to three-week transitional phase, hair follicles shrink and hair growth slows.
• Telogen: In this resting phase, hair stops growing but doesn’t fall out. The scalp stays in this stage for about two to three months.
• Exogen: Hair is actively shed from the scalp, which allows new hair to grow.

Other Reasons for Hair Loss Beyond Shedding Season

Beyond shedding season, there are several reasons that more hair might fall out than usual:

• Telogen Effluvium: This is a temporary form of hair loss triggered by stress, such as from illness, surgery, or nutrient deficiencies. It typically shows up a few months after the stressful event.
• Anagen Effluvium: Also a temporary condition, it’s most common after chemotherapy but can be associated with radiation or exposure to toxins. Hair may fall out quickly, but it typically grows back within a few months.
• Alopecia Areata: This is an autoimmune disease in which the immune system attacks the hair follicles, leading to patches of hair loss.
• Androgenetic Alopecia: Also known as female pattern hair loss, this is the most prevalent type of permanent hair loss in women. The hair thins at the crown of the head or the part line becomes wider. It’s a progressive, chronic condition that requires ongoing treatment.
• Nutritional Deficiencies: A diet lacking sufficient vitamins and minerals can have a negative impact on hair health.
• Hormonal Changes: Shifts in estrogen levels after pregnancy or due to thyroid disorders can disrupt the hair growth cycle and lead to increased shedding a few months later.

When to See a Doctor

If home care isn’t helping, or if your hair loss becomes more severe, see a dermatologist as soon as possible. If you have a hair loss issue beyond seasonal shedding, treatments are often most effective when started early.

Dr. Lupo says to see a dermatologist in these circumstances:

• Your hairline is moving back noticeably.
• You’re experiencing hair loss along with signs of hormonal issues, such as acne or irregular periods.
• You have excessive flaking.
• Your head or scalp is itchy.
• You have pustules or redness on your scalp.

Other common signs of hair loss in women include the following:

• Noticeable patches of thinner or missing hair
• Seeing scalp skin through your hair
• Noticing thinner ponytails
• Hair breakage

If hair loss becomes a significant, consistent issue, topical and oral medications like minoxidil or light therapy may be used for longer-term treatment.

Hair-Care Tips for Shedding Season

Experts say that the best way to minimize seasonal hair loss is to practice healthy hair and scalp habits.

• Use a gentle shampoo and apply moisturizing conditioner afterward to reduce breakage. “I like zinc-based shampoos,” which can help promote better hair health, says Lupo.
• Brush or comb hair gently. Avoid tight hairstyles.
• Reduce heat styling with blow dryers, curling irons, flat irons, and hot oil treatments.
• Stop playing with your hair.
• If you’re a smoker, quit.
• Eat a healthy diet rich in vitamin D, including fatty fish, egg yolks, and fortified cereals.
• Ask a doctor before taking any supplements, including vitamins, as they are not regulated by the U.S. Food and Drug Administration and may interact with other medications you are taking.