Telogen Effluvium

Telogen effluvium is a diffuse hair loss involving the entire scalp, which occurs without scarring or inflammation. There are three phases of the hair growth cycle, including the anagen or growth phase, catagen or involution phase, and telogen or the resting phase. Normally, about 10% of hairs are in a resting phase (telogen). One hundred telogen hairs are normally lost from the scalp each day.

In telogen effluvium, a certain precipitating event (some of which are listed below) shifts hairs into telogen. As a result, more than 10% (e.g. 20 or 30%) of scalp hair start their resting phase and get lost from scalp surface. Such hair loss is not permanent, since hairs only stay in a telogen phase for a limited amount of time. Once telogen phase is completed, hairs usually regrow.

Telogen effluvium usually occurs two to three months following various precipitating events. The most common causes include high fevers, severe emotional and physical traumas, surgical operations, crash diets, child birth, and certain medications. Hair re-growth can usually be seen by six months. To make the diagnosis of telogen effluvium, the physician may ask the patient to do a two-week hair count and may perform a hair pull test (where strands of hair are pulled from the scalp).

Daily hair counts of greater than 100 hairs and more than four easily pulled hairs (hair pull test) are suggestive of the diagnosis of telogen effluvium. The most important issue in telogen effluvium is finding a precipitating event or underlying cause. Often times, blood tests may be needed to find underlying causes.

Telogen effluvium presents with an acute onset of diffuse uniform hair loss involving the entire scalp. There is no redness or scarring of the scalp. The degree of shedding is usually much less than 50% of the total scalp hair. Telogen effluvium almost never results in total baldness.

Telogen effluvium does not require treatment and is usually self-limited. If a medication is found as the causative agent, discontinuation of the medication will result in resolution of the telogen effluvium.
In rare cases, a chronic type of telogen effluvium may occur. It usually lasts longer than six months, is found mostly in middle-age women, and may require a biopsy of the scalp to make the diagnosis. As is the case with acute telogen effluvium, it will not result in complete hair loss and will tend to resolve on its own.

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Sinclair R: Chronic telogen effluvium: A study of 5 patients over 7 years. J Amer Acad Dermatol 2005; 52 (2 Suppl 1): S12-S16.

Mollie Jan, D.O.
Department of Dermatology
Philadelphia College of Osteopathic Medicine/Frankford Hospital
Philadelphia, Pennsylvania.