Dermatology · Hair Disorders
The facts most likely to be tested
Telogen effluvium is a non-scarring alopecia characterized by the premature transition of hair follicles from the anagen (growth) phase to the telogen (resting) phase.
Patients typically present with diffuse hair shedding that occurs 2 to 3 months after a significant physiological or psychological stressor.
Common triggers include childbirth, severe febrile illness, major surgery, rapid weight loss, or severe nutritional deficiencies.
The hair pull test is positive, yielding more than 10% of hairs with club-shaped, non-pigmented bulbs under microscopic examination.
Physical examination reveals diffuse thinning of the scalp hair, most commonly involving the vertex and temporal regions, without evidence of inflammation or scarring.
The diagnosis is primarily clinical, based on a thorough history of a preceding stressor and the absence of scalp pathology or hair shaft abnormalities.
Management focuses on reassurance and identifying/correcting the underlying trigger, as the condition is self-limiting and typically resolves within 6 to 12 months.
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A 28-year-old female presents to the clinic complaining of increased hair loss over the past 6 weeks. She reports that she notices large amounts of hair in her brush and in the shower drain. Her medical history is significant for a complicated delivery of her first child 3 months ago. On physical examination, there is diffuse thinning of the scalp hair, but the scalp skin appears normal with no erythema, scaling, or scarring. A hair pull test is performed and results in the extraction of several hairs with club-shaped bulbs.
What is the most likely diagnosis?
Telogen effluvium
The patient's presentation of diffuse hair shedding 3 months postpartum, combined with a positive hair pull test showing club-shaped bulbs and a normal scalp exam, is classic for telogen effluvium, which is triggered by the physiological stress of childbirth.
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High yield triage
Etiology / Epidemiology
Triggered by physiologic stress (surgery, childbirth, severe illness) or nutritional deficiency (iron, protein).
Clinical Manifestations
Diffuse, non-scarring hair loss occurring 3 months after a precipitating event.
Diagnosis
Clinical diagnosis confirmed by a positive hair pull test (>10% of hairs extracted).
Treatment
Reassurance and addressing the underlying trigger; no specific pharmacologic cure exists.
Prognosis
Self-limiting condition with full recovery typically occurring within 6-12 months.
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Epidemiology & Etiology
Common in adults following significant systemic stressors including major surgery, high fever, or rapid weight loss. Postpartum hair loss is a classic presentation due to the withdrawal of high estrogen levels. Nutritional deficiencies, specifically iron deficiency anemia, are frequent reversible causes.
Pertinent Anatomy
The hair cycle consists of the growth phase (anagen), transition (catagen), and resting phase (telogen). Telogen effluvium involves the premature shift of follicles from the anagen phase to the telogen phase.
Pathophysiology
A systemic insult forces a large percentage of hair follicles into the resting phase simultaneously. After a latent period of approximately 3 months, these follicles enter the shedding phase. Because the process is diffuse, the scalp shows no evidence of inflammation or scarring.
Clinical Manifestations
Patients present with a sudden increase in daily hair shedding, often noticed during brushing or showering. The scalp remains healthy with no erythema or scaling, distinguishing it from inflammatory alopecias. Red flags such as patchy hair loss or scalp tenderness suggest alternative diagnoses like alopecia areata or fungal infections.
Diagnosis
The hair pull test is the gold standard; grasping a bundle of 50-60 hairs and pulling gently yields >6 hairs in the telogen phase. Laboratory evaluation should focus on serum ferritin and TSH to rule out correctable metabolic triggers. A scalp biopsy is rarely indicated unless the diagnosis is unclear.
Treatment
Management centers on identifying and correcting the precipitating stressor. Patients require significant reassurance that the condition is self-limiting. Avoid unnecessary supplements unless a specific deficiency is confirmed via laboratory testing. If iron deficiency is present, oral ferrous sulfate is the standard replacement.
Prognosis
The condition is almost always reversible once the trigger is removed. Full hair regrowth is expected within 6 to 12 months. If shedding persists beyond this window, clinicians must re-evaluate for chronic underlying pathology.
Differential Diagnosis
Androgenetic alopecia: pattern-based thinning rather than diffuse shedding
Alopecia areata: well-circumscribed, smooth, round patches of hair loss
Tinea capitis: presence of scaling, crusting, or broken 'black dot' hairs
Anagen effluvium: rapid hair loss occurring days after chemotherapy
Trichotillomania: irregular patches with hairs of varying lengths