Telogen effluvium (TE) is one of the most common causes of sudden or diffuse hair loss in both men and women. Unlike androgenetic alopecia, which develops slowly over years, telogen effluvium typically presents as sudden, alarming hair shedding — often within 2–4 months of a triggering event.
What Is Telogen Effluvium?
Under normal conditions, approximately 85–90% of scalp hairs are in the anagen (active growth) phase at any given time, with 10–15% in the resting telogen phase. Telogen hairs are shed naturally after 2–3 months of resting.
A physiological shock — physical or psychological — can cause a large proportion of anagen hairs to simultaneously enter the telogen phase. Two to four months later, these hairs shed simultaneously, causing a sudden, noticeable increase in shedding.
Common Triggers
- Physical illness or surgery (including COVID-19)
- Significant psychological stress
- Major weight loss or crash dieting
- Nutritional deficiency (iron, zinc, protein, vitamin D)
- Childbirth (post-partum telogen effluvium — extremely common)
- Starting or stopping hormonal contraception
- Thyroid dysfunction
- Anaemia
How Severe Can It Be?
TE can cause dramatic shedding — patients sometimes lose 30–50% of scalp hair density. While alarming, the follicles themselves are not damaged — they are simply in a resting phase. This means the condition is reversible once the trigger is resolved.
How Long Does It Last?
Acute TE typically resolves within 6–12 months of the triggering event resolving. Regrowth begins 3–6 months after shedding stops. Some patients develop chronic TE (lasting more than 6 months) — these cases require more thorough investigation.
When to Seek Help
Seek assessment when:
- Shedding is severe or persistent
- No obvious trigger can be identified
- Shedding does not improve after 6 months
- There is concern about associated androgenetic alopecia (the two can coexist)
Blood tests: ferritin, full blood count, thyroid function, zinc, vitamin D, and hormonal panel identify the most common correctable causes.
Can Hair Transplant Help?
Hair transplant is not appropriate for active telogen effluvium. The follicles are temporarily dormant — not permanently lost. Treatment and time are the appropriate interventions. Transplantation for TE would be premature and could result in transplanting into an unstable scalp.
Experiencing sudden or diffuse hair loss? Our team will help identify the cause and distinguish TE from other forms of hair loss that may require different treatment.