Telogen is the name for the resting stage of the hair growth cycle. Telogen Effluvium is when stress or other factors causes hair growth to prematurely enter the resting stage in the hair growth cycle.
If there is some “shock to the system”, as much as 70% of the scalp hairs are then shed in large numbers in about 2 months. This sudden increase in hair loss, usually described as the hair coming out in a large number is described as acute telogen effluvium. This is different from genetic hair thinning. However, this can considered as less common chronic telogen effluvium, only after a significant amount of hair loss has occurred.
There are a considerable number of different causes for the occurrence of telegon effluvium. Amongst the common causes are high fevers, child birth, severe infections, severe chronic illness, severe psychological stress and major surgery or illness. Most hair loss also occurs from using medication.
Typically, abrupt diffuse hair loss can be noticed in about several weeks to several months after an incident has initiated the biological program of hair loss. Most often hair loss is noticed on the scalps but individuals might also notice hair loss on different parts of the body. Significant hair loss can be seen when shampooing or combing. Shedding usually slowly decreases over 6 to 8 months once the cause for the hair loss is no longer present.
These shed or loose hairs all have club-shaped “roots” typical of resting, telogen hairs and can be easily identified under a microscope. After shampooing, the bulk of existing loose hair has often been shed and loose hair may not again appear until additional hairs enter this resting phase.
No treatment is needed for most cases of telogen effluvium. Remember that the hairs fall out when a new hair growing beneath it pushes it out. Thus with this type of hair loss, hair falling out is a sign of regrowth. As the new hair first comes up through the scalp and pushes out the dead hair a fine fringe of new hair is often evident along the forehead hairline.
The most important issue in telogen effluvium is to determine if an underlying cause for the problem is present. Blood tests may be needed if the cause is not obvious, such as mild iron deficiency. If the telogen effluvium is caused by a medication, the medication needs to be stopped. When the cause of the hair loss is something like giving birth, a transient illness, or other self-limited problem the induced telogen effluvium is also usually self-limited and requires no treatment.