By Maria Serraino

We’ve all been there. Staring at the sink covered in hair after we finish combing, or trying to unclog the drain of all the hair that we shed in the shower. Hair shedding is completely normal and very common, but how much hair loss is too much? And when does it become a problem? Dr. Charlene Linzon, director of the University of Toronto Hair Loss Clinic at Women’s College Hospital, department of dermatology, is getting down to the basics and explaining everything from the hair cycle to hair loss.

The hair cycle

“It’s important to understand the normal hair growth cycle in order to fully understand why and how hair loss occurs,” Dr. Linzon says. Hair grows in a repeating cycle of stages, including anagen (the growth stage) and telogen (a period of rest).

“In the scalp of a healthy adult, up to 90 per cent of scalp hair will be in anagen. The other 10 per cent is in telogen,” she explains. This means that most of the hair on our head is in the growing phase. A hair grows for three to six years and then falls out after two to three months (once a new hair shaft emerges) and the natural cycle restarts.

We are born with about 100,000 hairs on our scalp. On average 50 to 100 telogen hairs are normally shed every day. These hairs are randomly distributed throughout the scalp, so the fallout is barely noticeable and accounts for the hair we lose in the shower and when combing. Hair will re-grow in these same spots and will enter the anagen phase. 

“A problem lies when there is an increase in the number of hairs in the telogen phase and anagen is shortened,” says Dr. Linzon. Here, the hair loss is more visible. 

Types of hair loss

There are two types of hair loss: scarring and non-scarring. Scarring hair loss is associated with the permanent destruction of the hair follicle, while non-scarring refers to hair loss without destruction of the hair follicle.

Scarring hair loss is less common, but should be seen immediately by a doctor for treatment.  

Non-scarring hair loss is more common. A specific form of non-scarring hair loss is alopecia areata, which is an autoimmune disease that causes hair to spontaneously fall out. It occurs in about two per cent of the population. It is characterized by bald patches on the scalp or other parts of the body. Alopecia areata occurs in males and females of all ages.

Another common form of hair loss is androgenetic alopecia, or AGA. It is usually referred to as male or female pattern baldness. AGA is hereditary, occurs in about 50 per cent of the population, both males and females, and can be caused by changes in the levels of androgens (male hormones). It is a condition in which the anagen phase of the normal hair cycle shortens and the new hair regrows but is miniaturized.

“Over time hairs fall out, leaving a characteristic pattern of diffuse thinning in the central part,” says Dr. Linzon. “There is some individual variation of course, but it tends to become thin on the top and crown, leaving the frontal hairline intact.” The pattern of hair loss in females is different than in males.  In males, the hair loss progresses in a recognizable pattern to total or near baldness.   

Dr. Linzon explains that another common type of non-scarring alopecia is chronic telogen effluvium or CTE. It is a form of shedding caused by stress and occurs mainly in adult women. CTE is characterized by diffuse thinning and is marked in the temple area. Women with CTE usually complain of more than the average 100 hairs falling per day. In CTE the anagen phase is decreased and hair may not grow for as long as it normally should before entering the telogen phase. This results in an increase of up to 40 per cent of hairs in the telogen phase, compared to the usual 10 per cent.

CTE can resolve on its own when stress is properly controlled, although this may take years. Unfortunately, it requires some waiting to see if the hair will grow back, if at all. Women experiencing CTE often complain that they can’t wear their hair in a ponytail because the hair is not dense enough.

“Patients often say that they had thick hair before, but a drastic event may be the cause of the condition,” says Dr. Linzon. Common causes of CTE include sudden weight loss of over 10 pounds, a big move to a new country, new job, marital or financial stress, illness, major physical trauma and severe psychological stress. Unfortunately, the shedding itself may increase stress levels for many women, only furthering the problem.

Treatment

While experiencing hair loss can be devastating, Dr. Linzon reassures patients that they are not necessarily losing their hair, just experiencing increased shedding. Patients who are worried that they are shedding too much hair should consult their doctor. If hair loss is a problem, there are certain treatments recommended for specific conditions. Minoxidil is a commonly used topical treatment. It helps by increasing the length of time that hair stays in the anagen cycle. Two per cent minoxidil can be purchased over-the-counter and is usually recommended for use twice daily. However, minoxidil does have side-effects, including increased hair growth on the face.

“If you notice a change in your hair, see your physician,” Dr. Linzon says. “The sooner you address the potential problem, the faster we can help.”