What is Telogen?
Telogen is one of the phases of the
hair growth cycle. It is the resting phase that follows the
anagen (growth phase) and
catagen (transition phase) phases. During the telogen phase, hair follicles are in a state of rest, and hair strands are not actively growing but are retained in the follicle.
Duration of Telogen Phase
The telogen phase typically lasts for about 2 to 3 months. However, the duration can vary depending on factors like age, health, and genetic predisposition. In a healthy scalp, about 10-15% of hair follicles are in the telogen phase at any given time.Histological Characteristics
Under the microscope, hair follicles in the telogen phase exhibit several distinctive features. The follicle shrinks and moves closer to the surface of the scalp. The
hair bulb is not as prominent as in the anagen phase, and the dermal papilla is less active. The
outer root sheath and
inner root sheath are less developed, and the hair shaft is club-shaped.
Function and Importance
The telogen phase serves an important function in the hair growth cycle. It allows the follicle to rest and prepare for the next cycle of growth. This phase is crucial for the health and regeneration of hair as it prevents continuous stress on the hair follicle, thereby reducing the risk of damage.Clinical Relevance
In clinical settings, the telogen phase is often examined in conditions like
telogen effluvium, where an abnormal number of hair follicles enter the telogen phase, leading to significant hair shedding. Understanding the histological characteristics of telogen can help in diagnosing such conditions and guiding appropriate treatment plans.
Diagnostic Techniques
Several diagnostic techniques are used to evaluate the telogen phase.
Trichogram and
scalp biopsy are commonly employed methods. These techniques involve examining hair samples and scalp tissue under a microscope to identify the proportion of hair follicles in different phases of the hair growth cycle.
Factors Affecting the Telogen Phase
Various factors can influence the duration and characteristics of the telogen phase. These include hormonal changes, nutritional deficiencies, stress, and certain medications. Understanding these factors is essential for maintaining healthy hair and addressing issues related to abnormal hair shedding.
