Telogen effluvium — diffuse hair shedding triggered by a physiological stressor — is the most common cause of sudden hair loss we see in clinical practice. It is also one of the most anxiety-inducing for patients, because the shedding can be dramatic (hundreds of hairs per day) and the cause may not be immediately obvious. Understanding the mechanism removes much of the fear.

The Hair Cycle and Why Shedding Happens

Hair grows in cycles: anagen (active growth, 2-7 years), catagen (transition, 2-3 weeks), and telogen (resting, approximately 3 months) before the hair sheds and the cycle restarts. Normally, approximately 10-15% of hairs are in telogen at any given time, and daily shedding of 50-100 hairs is normal. In telogen effluvium, a significant trigger — physical or emotional — causes a large proportion of anagen hairs to prematurely enter telogen simultaneously. Three months later (the telogen resting period), those hairs all shed together, producing the sudden increase in shedding that patients notice.

Common Triggers in Indian Patients

The triggers we see most frequently: acute illness (including COVID-19, typhoid, dengue), major surgery, significant emotional stress, crash dieting or sudden weight loss, childbirth, stopping oral contraceptives, thyroid dysfunction, and iron deficiency anaemia (extremely common in Indian women). The three-month lag between trigger and shedding is clinically important — patients often cannot identify the cause because they are looking at recent events when the relevant trigger was 3 months earlier.

Assessment and Treatment

Diagnosis involves a clinical history focusing on events 2-4 months prior to the onset of shedding, a gentle pull test to assess current shedding activity, and blood tests — complete blood count, ferritin, thyroid function, vitamin D, and B12. Treating identified deficiencies is the primary intervention. Iron supplementation in iron-deficient patients consistently produces meaningful improvement in hair shedding. Most episodes of telogen effluvium resolve spontaneously within 6-12 months once the trigger is addressed. For persistent or severe cases, minoxidil supports the hair cycle back to normal activity, and GFC therapy provides additional follicular support.

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— Dr. Nishita Ranka | Consultant Dermatologist | Dr. Nishita’s Clinic for Skin, Hair & Aesthetics, Hyderabad