What is Telogen Effluvium?

Telogen effluvium (TE) is a form of temporary, diffuse hair shedding that occurs when a significant number of follicles are simultaneously pushed from the active growth phase (anagen) into the resting phase (telogen), followed by mass shedding. Under normal circumstances, only about 10–15% of follicles are in the telogen phase. In TE, this rises to 30–50% — resulting in widespread, alarming shedding.

The most important thing to understand: the follicles are not destroyed. They are dormant, not dead. In the vast majority of cases, once the underlying trigger resolves, follicles re-enter the anagen phase and hair regrows — often completely.

2–4
months delay between trigger and shedding
90%
of cases fully reversible
6–12
months typical recovery timeline

The Characteristic Delay — Why Hair Falls Out Months Later

The most confusing aspect of telogen effluvium is its delayed onset. The trigger — illness, surgery, stress, childbirth — occurs at one point in time. The visible hair shedding begins 2–4 months later. By the time shedding starts, many patients have forgotten the original trigger or don't connect it to their hair loss.

The reason: when a stressful event occurs, follicles are forced into the telogen phase. They then spend the normal telogen duration — approximately 2–4 months — resting before the hairs are shed as new growth pushes them out. So the shedding you experience in month 3 was actually triggered in month 1.

💡 Clinical Pearl

When evaluating any patient with sudden diffuse hair loss, Dr. Ashwini always takes a detailed history of events in the 2–6 months BEFORE the shedding began — not in the weeks immediately preceding it. The trigger is almost always found in that earlier window.

Common Triggers

  • Childbirth & Postpartum: The dramatic drop in oestrogen after delivery triggers widespread follicle entry into telogen. Affects up to 90% of new mothers to varying degrees. Usually self-resolving within 12–18 months.
  • Significant illness or surgery: Any major physical trauma — major surgery, hospitalisation, severe infection (including COVID-19 and dengue fever) — can trigger TE. COVID-19-related TE became one of the most common forms seen in clinics globally from 2020.
  • Crash dieting & rapid weight loss: Severe caloric restriction deprives follicles of essential nutrients and can trigger TE 2–3 months after the weight loss.
  • Severe psychological stress: Bereavement, divorce, job loss, major relationship breakdown, and other acute psychological traumas can precipitate TE.
  • Iron deficiency: Particularly in menstruating women — severe iron deficiency (low ferritin) can trigger or perpetuate chronic TE. Ferritin testing is standard in any hair loss evaluation.
  • Thyroid dysfunction: Both hypothyroidism and hyperthyroidism cause diffuse hair loss presenting similarly to TE.

Recovery Timeline

  1. Months 1–2 after trigger: Follicles entering telogen phase. No visible shedding yet. Hair may begin to feel less voluminous.
  2. Months 2–4 after trigger: Shedding begins and intensifies. Shower drain and hairbrush losses are alarming. This is the peak — meaning things are about to improve.
  3. Months 4–6 after trigger: Shedding begins to slow as follicles re-enter anagen. Fine, short new hairs appear along the scalp — particularly the hairline. These "baby hairs" are a very positive sign of recovery.
  4. Months 6–12 after trigger: Significant regrowth visible. Hair volume and density improving. Most patients see substantial recovery during this period.
  5. Months 12–18 after trigger: Full recovery expected in the majority of cases. Hair density returns to pre-trigger levels.
⚠️ When to Seek Treatment

If shedding has not shown clear improvement by 6 months, or hair density has not substantially recovered by 12–18 months, seek specialist assessment. This may indicate ongoing nutritional deficiency, underlying androgenetic alopecia unmasked by the TE, or chronic TE requiring specific treatment.

Treatment & Management

  • Address the underlying cause first: Iron deficiency → correct with supplementation (iron + vitamin C). Thyroid dysfunction → treat medically. Triggering medication → discuss alternatives with prescribing doctor.
  • Nutritional optimisation: Ensure adequate protein, iron (ferritin target >70 ng/mL), vitamin D, zinc, and B vitamins.
  • Minoxidil: Accelerates recovery by extending the anagen phase — particularly useful when there is an underlying androgenetic component.
  • PRP/GFC Therapy: Growth factor injections can significantly accelerate follicle recovery and shorten the recovery timeline. Highly recommended for cases that are slow to recover or where significant density has been lost.
  • Stress management: For stress-triggered TE, addressing the underlying stress — through counselling, mindfulness, exercise, and adequate sleep — supports overall recovery.

Frequently Asked Questions

How can I tell if my hair loss is TE or androgenetic alopecia?
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TE tends to be diffuse (affecting the whole scalp), sudden in onset, and temporally linked to a trigger. Androgenetic alopecia follows characteristic patterns (Norwood or Ludwig) and is gradual. A trichoscopy examination by Dr. Ashwini can reliably differentiate the two — and identify when both are present simultaneously.
I had COVID-19 and now my hair is falling out. Is this related?
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Almost certainly, yes. Post-COVID telogen effluvium became one of the most commonly reported hair loss conditions globally from 2020 onwards. Shedding typically begins 2–3 months after the infection and peaks at 3–5 months. The majority of post-COVID TE cases resolve completely within 12 months. PRP therapy can accelerate recovery significantly.
Can I prevent TE from happening after surgery?
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Complete prevention is not always possible, but ensuring excellent nutritional status before and after surgery — particularly iron, protein, and vitamin D — reduces severity. Discussing adequate nutrition in the recovery period with your surgical team is also important.