Telogen effluvium
Introduction
Telogen effluvium (TE) is a common form of hair loss characterized by diffuse shedding of hairs. It occurs when a significant number of hair follicles prematurely enter the telogen (resting) phase. Dermoscopy, or trichoscopy when referring to hair and scalp, is an invaluable tool in diagnosing TE, allowing for detailed visualization of the scalp and hair follicles.
Etiology and Pathophysiology
TE typically results from a disruption in the hair cycle due to various triggers such as severe illness, stress, hormonal changes, nutritional deficiencies, or medications. This disruption leads to an increased proportion of hairs in the telogen phase, causing noticeable hair shedding.
Dermoscopic Features of Telogen Effluvium
Hair Density
- Reduced hair density is a hallmark of TE, more apparent through trichoscopic examination.
Hair Diameter Diversity
- TE often shows a normal range of hair shaft diameter, contrasting with the variability seen in androgenetic alopecia.
Telogen Hairs
- An increased number of telogen hairs, characterized by a white bulb at the end, are visible.
Scalp Features
- The scalp usually appears normal without significant erythema, scaling, or scarring.
Differential Diagnosis
Trichoscopy is crucial in differentiating TE from other forms of alopecia, particularly:
- Androgenetic Alopecia (AGA): Noted for increased hair shaft diameter variability.
- Alopecia Areata (AA): Exhibits exclamation mark hairs and yellow dots.
Diagnostic Criteria
While there is no exclusive trichoscopic criteria for TE, a combination of clinical history, hair pull test, and trichoscopic features aids in diagnosis. The presence of an increased number of telogen hairs and uniform hair shaft diameter are supportive findings.
Management and Prognosis
TE is generally a self-limiting condition. Management focuses on identifying and addressing the underlying cause. Nutritional supplementation, stress management, and topical minoxidil are commonly used treatments. The prognosis is generally good, with hair density typically returning to normal once the triggering factor is resolved.
Conclusion
Dermoscopy/trichoscopy plays a significant role in diagnosing telogen effluvium, offering a non-invasive method to assess the hair and scalp. Its use is pivotal in differentiating TE from other forms of hair loss and in guiding appropriate management strategies.
