Telogen and anagen hair loss

Analysis of various functional types of telogen hair loss allows the doctor to correctly determine the probable time interval (from several days to several months) to effectively search for the cause of diffuse alopecia in the patient.

Telogenovoe hair loss

This is an excessive prolapse of normal hair in the telogen phase. Currently, there are 5 functional types of this syndrome.

1. Premature termination of the anagen phase is the most frequent reaction of follicles to the effect of provoking factors (medication intake, high fever, surgical intervention, blood loss, starvation, etc.). Hair follicles, which for a long time should have been in the growth phase, prematurely enter the telogen phase; the process ends with a profuse loss of hair 3-5 weeks after the action of the factor.
2. Later, the completion of the anagen phase is characteristic of postpartum hair loss. Metabolic and endocrine changes during pregnancy, especially in the last trimester, cause lengthening of the anagen phase. Most follicles (95%) are in the growth phase and do not go catagen before the birth of the child. After birth, these follicles quickly enter the phase of catagen and telogen, which leads to profuse hair loss 1-2 months after birth.

A similar in mechanism hair loss occurs when discontinuing oral contraceptives.

3. The shortened phase of the anagen is considered to be an idiopathic process. Patients complain of some increase in hair loss and inability to grow hair of the usual length. Syndrome "shortened anagen" is stated only after the elimination of androgenic alopecia, for which the gradual shortening of the hair growth phase is also characteristic. In contrast to androgenic alopecia, with telogen hair loss there is no atrophy of the follicles and a decrease in the thickness of the hair shaft, there is no expansion of the central part.
4. Premature termination of the telogen phase is characterized by a significant shortening of the resting phase, the normal duration of which is 4-6 weeks. Clinical manifestations appear several days after the action of the provoking factor, more often drug. In particular, this is the mechanism of hair loss with local use of a solution of minoxidil, which contributes to the rapid entry of the follicle to the next phase of growth.
5. Later, the completion of the telogen phase is possible in people living in a short daylight (northern latitudes). With the increase in the duration of daylight, hair loss increases; a characteristic decrease in daily hair loss during the winter period of the year remains, as a rule, unnoticed.

Anagen hair loss

This excess hair loss in the phase of anagen, which is observed in patients with malignant neoplasms as a response to cytostatic and radiation therapy. Hair loss begins suddenly, 4-10 days after exposure, and can lead to total baldness. Sometimes the cause of anagenic alopecia is poisoning with arsenic, thallium, pesticides. The action of the above factors is based on the suppression of mitoses in the cells of the matrix of the hair follicle and the violation of cell differentiation. Hair becomes dystrophic, narrowed in the proximal part, often break off; end with a cone-shaped pigmented bulb.

[1], [2], [3]