Telogen Hairs: Terminal, Miniaturizing and Vellus

Telogen Hairs: More than a Single Type!

Hair that are firmly rooted in thr scalp and don’t seem to want to come out are mostly “anagen hairs.” In contrast, hairs that can be pulled out and hairs that are going to fall out today, tomorrow or this month are called “telogen hairs.”

There are many types of telogen hairs rather than just one. Long thick hairs are called terminal telogen hairs and they are typically 70 micrometers or more in diameter. Miniaturizing hairs are a type of so called intermediate hair are thinner and are most commonly seen as part of the spectrum of changes seen in androgenetic alopecia (but other conditions like alopecia areata, traction may give some degree of miniaturization).

Telogen hairs that are short, pale and thin are called telogen vellus hairs. They too are commonly found in males and females with androgenetic alopecia but are difficult to see because they are so short and pale in color. This photo shows a 37 micrometer telogen “miniaturizing” hair from a patient with androgenetic alopeca. A relatively unaffected hairs (telogen terminal hair) is seen in the upper left. The precise cut off values for normal hair thickness differ somewhat according to the ethnic background of the patient.