What is telogen effluvium?
On the normal scalp about 95% of the hairs are in the growth phase (anagen), a few follicles are moving from growth to resting phase (catagen) and 5% are in the resting phase (telogen). The growing hairs all have a growth cycle that is independent of the others on the head. Each hair on the scalp grows for 1 to 3 years before entering the resting phase, which lasts about 3 months. On average, about 80 to100 hairs are lost each day. These are hairs that have reached the end of resting phase. These hairs are seen accumulating in the brush/comb, or the drain in the bathroom.
On the scalp the hair growing period is longer, which is why the hairs on the scalp are longer than hairs on other parts of the body.
When a large number of hair follicles simultaneously enter the telogen phase, increased shedding of hair occurs.
What causes telogen effluvium?
Telogen effluvium results when the normal ratio of growing and resting hairs is altered, and the percentage of hair follicles in telogen is increased. The hair shedding is usually noted 3 to 4 months after the trigger.
The triggers for telogen effluvium can be physiological or pathological. There are no symptoms or changes seen in the scalp skin.
In newborns and after childbirth, large numbers of hair follicles are programmed to enter telogen phase at the same time. Significant shedding postpartum (after childbirth) is common. These are both considered to be physiologic telogen effluvium.
Emotional stress due to a major life event (such as severe trauma, loss of a loved one, change in employment) is a common trigger. Severe illness, surgical operations, high fevers (especially if prolonged), thyroid dysfunction and autoimmune conditions such as systemic lupus erythematosus are also known to trigger telogen effluvium. In some cases, there may be a nutritional deficiency in association with crash dieting, significant weight loss or anorexia nervosa.
Some medications are known to be associated with telogen effluvium. These include some blood pressure tablets, anti-epileptic medications, high doses of vitamin A, oral retinoids and blood thinning agents. Stopping oral contraceptives can also trigger telogen effluvium.
In some people, a cause may not be identified.
Telogen effluvium can last between 3 to 12 months.
Chronic telogen effluvium is where the hair shedding lasts more than 6 months. This is more common in middle-aged women who often report long, thick hair prior to the onset of hair shedding. Chronic telogen effluvium may occur at the same time as female pattern hair loss (androgenetic alopecia).
What are the symptoms of telogen effluvium?
Affected individuals experience an increase in hair shedding which is apparent with shampooing or brushing. This is associated with diffuse (all over) thinning of the hair. This may not be so obvious to others but those affected by it often report a significant reduction in hair volume.
How is telogen effluvium diagnosed?
The diagnosis is suggested on clinical history and examination. The dermatologist is often able to demonstrate a positive hair pull test. This is where a handful of hair is pulled with firm traction. A positive pull test is where 4 to 6 hairs are extracted, indicative of active hair shedding. Biopsies may be needed to exclude other causes of hair loss such as alopecia areata or androgenetic alopecia. Your dermatologist may request a blood test to rule out an underlying cause for your hair loss.
How is telogen effluvium treated?
Even though this condition can be very alarming and distressing, telogen effluvium is a temporary, self-limiting hair loss condition. Regrowth is expected in most cases, often within 6 to 9 months, although it may take longer.
There is no medical treatment that can be given to hasten the hair growth. The hair normally grows about 1cm a month so it takes about 9 to12 months for the hair to regain its original thickness. Your doctor will look at the margins of the scalp. It is easier to see the regrowth occurring at these sites. The degree of regrowth experienced depends on age, hormones, genetics and general health. Some people experience complete regrowth. Peri-menopausal and post-menopausal women often experience less regrowth than younger women as there is an age-related reduction in the total numbers of active hair follicles as an individual ages.
Identifying and addressing any triggers such as nutritional deficiencies can be helpful. It may be useful to seek psychological support given stress is commonly a trigger and the hair loss itself is often very distressing for the affected individual.
Telogen effluvium can return in some individuals if the underlying trigger recurs.
This information has been written by Dr Yin Vun
Updated 15 February 2016