In short
Telogen effluvium is sudden, diffuse hair shedding that starts a few months after a trigger: a high fever, childbirth, a strict diet, a stressful period or a deficiency. It does not cause bald patches and usually settles once the cause is corrected. The key is to find that cause and rule out another type of hair loss.
Key points
- Shedding shows up around three to four months after the trigger, not at the time.
- It is one of the most common causes of diffuse hair loss, and women seek help for it most often.
- It usually resolves once the cause is corrected; no specific treatment shortens it.
- A ferritin blood test helps rule out low iron, a common and treatable cause.
- It can coexist with pattern hair loss, which does need treatment.
Finding hair blocking the plughole or on your pillow is frightening. The reassuring part is that sudden, all-over shedding is usually telogen effluvium: a shift in the hair cycle that almost always has a cause and, once that cause is dealt with, recovers. This guide explains why it happens, what sets it off and when to see a doctor.
What telogen effluvium is
Every hair lives in cycles. It spends a few years growing (the anagen phase) and a few months resting (the telogen phase), until a new hair pushes it out and it falls. In a healthy scalp, around 85% of hairs are growing and about 15% are resting [2].
In telogen effluvium, a shock to the body pushes many hairs into the resting phase at the same time. Months later, all those hairs fall within a short period [2]. That is why the shedding does not coincide with the cause: it shows up around three to four months after the trigger [1].
It is one of the most common causes of diffuse hair loss, and women seek help for it most often [1]. It does not leave bald patches: the hair thins all over. Some people also notice scalp discomfort or tenderness, known as trichodynia [3].
What triggers it
The causes vary widely. The most common are [2]:
- High fever or serious infections. After COVID-19, a review of 465 patients found shedding began on average 74 days later, slightly earlier than usual, and that most people recovered [7].
- Major surgery or serious injury.
- Intense emotional stress, such as bereavement, a break-up or a period of heavy pressure [9].
- Childbirth. It is one of the most frequently cited causes, although how often it really happens is poorly measured and some authors question it [8].
- Very restrictive diets and rapid weight loss, particularly with too little protein [4].
- Deficiencies, with low iron the most studied.
- Thyroid problems, especially an underactive thyroid.
- Stopping hormonal contraception or changing hormone treatment.
- Some medicines, such as certain beta blockers, retinoids or anticoagulants, or too much vitamin A.
Several causes often combine, for example a strict diet during a stressful time. A move abroad can bring several at once. And sometimes no clear cause turns up.
How it is diagnosed
Diagnosis rests mainly on a careful history: what happened in the preceding months, when the shedding began and how. Seeing lots of resting hairs fall confirms telogen effluvium, but it does not explain why. For that you need the history and, often, a blood test to rule out hormonal, nutritional or autoimmune causes [1].
Shedding can be measured by examining the hair that comes out on washing or with a trichogram; a scalp biopsy is rarely needed [9]. Trichoscopy helps rule out other types of hair loss. With guided photos of the scalp, the pattern and its progress can be assessed remotely.
Blood tests usually include a full blood count, ferritin and thyroid function, plus others depending on your history. Ferritin is a sensitive and specific marker of iron deficiency in diffuse hair loss [6]. In Spain it is reported in ng/mL, which is numerically the same as the µg/L you may see on a UK report.
A key part of the diagnosis is telling telogen effluvium apart from pattern hair loss, because the two often coexist [3]. An episode of shedding can unmask pattern hair loss that was progressing quietly. If that sounds familiar, read what works for male and female pattern hair loss.
Telling it apart from other hair loss
These clues help, but they do not replace a medical consultation:
- Telogen effluvium. Sudden, diffuse shedding of whole hairs with a small white bulb at the root, starting months after a trigger. No bald patches.
- Pattern hair loss. Slow thinning over years, in a pattern: temples and crown in men, a widening parting in women. Hair becomes finer before it falls.
- Alopecia areata. Round, sharply defined bald patches that can appear within weeks, sometimes in the beard or eyebrows.
- Scarring alopecias. Hairless areas where the skin is smooth, shiny or red, sometimes itchy or painful. These need an in-person consultation soon, because follicles can be lost permanently.
How it is treated
The main treatment is finding and correcting the trigger [9]. That might mean treating low iron, managing a thyroid problem, reviewing a medicine with your doctor or getting enough protein back into your diet.
There is currently no specific treatment that shortens telogen effluvium; the options tried have little evidence [4]. Vitamin and mineral supplements make sense when there is a deficiency; without one, no trials show that they improve shedding [5].
If the effluvium has unmasked pattern hair loss, that does have evidence-based medical treatment, and it is worth starting early.
What the evidence says
Each statement shows its level of evidence and the sources behind it.
Supported
With caveats
- After infections such as COVID-19, shedding has been reported to start slightly earlier than usual and, in most cases, to recover.[7]Moderate evidence
Not enough support
- How often hair loss genuinely follows childbirth is poorly measured: it is widely cited, but objective data are scarce.[8]Low-quality evidence
- Taking vitamin or mineral supplements without a proven deficiency has not been shown to improve shedding; large trials are lacking.[5]Low-quality evidence
- There is currently no targeted treatment that shortens telogen effluvium; the options tried have little evidence.[4]Experimental
When the hair grows back
Most acute episodes settle once the cause is corrected [4]. First the shedding slows. Then new, short hairs appear, which you notice when you style your hair.
Recovery is slow, because hair grows slowly. Getting back to your previous volume takes months. If shedding drags on for a long time or keeps coming and going, it is called chronic telogen effluvium, which needs a more detailed work-up [2].
Take it seriously, even though it is temporary. Shedding can weigh heavily on your mood, and it deserves time and attention [3].
How we approach it at Rejuvelook
We start with an online hair diagnosis by video consultation, in English or Spanish, from anywhere in Spain. We ask for guided photos of your scalp and go through the months before the shedding with you: illness, pregnancy, diet, stress and medication.
If your history suggests it, we request a blood test at a laboratory near you and go through the results together. The doctor then explains the likely cause and what to do. If there is also pattern hair loss, we propose a plan for it. If something does not fit telogen effluvium, such as bald patches or an inflamed scalp, we tell you and refer you for an in-person consultation or to a dermatologist.
When to see a doctor
Book a medical consultation, or go to A&E if it is severe or sudden, if you notice:
- The shedding lasts more than a few months or there is no obvious recent trigger.
- Round bald patches or distinct hairless areas appear, rather than all-over thinning.
- You feel very tired, look pale, notice weight changes, palpitations or very heavy periods.
- Your scalp is painful, very itchy, scaly or red.
- The shedding comes with a fever or other general symptoms: seek help without waiting.
- It started when you began or changed a medicine: tell your doctor, but do not stop it on your own.
Frequently asked
Will telogen effluvium make me go bald?
No. Telogen effluvium affects the hair cycle; it does not destroy the follicle. That is why hair grows back once the cause is corrected. If density does not recover, another cause needs looking for.
Should I wash my hair less or cut it short?
There is no need. Washing does not cause more shedding: it simply rinses out hair that had already come loose. Wash and brush as usual, gently.
Do hair vitamins help?
They help if you are short of something. If a blood test shows a deficiency, such as low iron, correcting it is part of the treatment. Without a deficiency, there is no solid evidence that a supplement stops shedding.
I recently moved to Spain. Could that be the cause?
It can play a part. A move often brings stress, disrupted sleep and changes in diet, sometimes all at once. Your doctor will look at the months before the shedding started as a whole, not at one event in isolation.
My blood test results use different units from home. Is that a problem?
No. Ferritin is reported in ng/mL in Spain, which is the same value as µg/L used in the UK. Your doctor explains the results in English and can give you a written summary for your GP.
How often should I take photos to track progress?
Once a month is enough, with the same light, hairstyle and angles. Daily photos are misleading: change is slow and shows up better month to month.
Can it happen again?
Yes. If another trigger comes along, such as an illness with a high fever or a very restrictive diet, hair can shed in the same way a few months later.
References
Sources checked against PubMed or Crossref. Cited as plain text, without links.
- 1.Malkud S. Telogen Effluvium: A Review. J Clin Diagn Res. 2015;9(9):WE01-3. doi: 10.7860/JCDR/2015/15219.6492. PMID: 26500992.Verified on 2 October 2026
- 2.Hughes EC, Syed HA, Saleh D. Telogen Effluvium. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024. PMID: 28613598.Verified on 2 October 2026
- 3.Rebora A. Telogen effluvium: a comprehensive review. Clin Cosmet Investig Dermatol. 2019;12:583-590. doi: 10.2147/CCID.S200471. PMID: 31686886.Verified on 2 October 2026
- 4.Chien Yin GO, Siong-See JL, Wang ECE. Telogen Effluvium - a review of the science and current obstacles. J Dermatol Sci. 2021;101(3):156-163. doi: 10.1016/j.jdermsci.2021.01.007. PMID: 33541773.Verified on 2 October 2026
- 5.Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019;9(1):51-70. doi: 10.1007/s13555-018-0278-6. PMID: 30547302.Verified on 2 October 2026
- 6.Zhang D, LaSenna C, Shields BE. Serum Ferritin Levels: A Clinical Guide in Patients With Hair Loss. Cutis. 2023;112(2):62-67. doi: 10.12788/cutis.0837. PMID: 37820340.Verified on 2 October 2026
- 7.Hussain N, Agarwala P, Iqbal K, Omar HMS, Jangid G, Patel V, et al. A systematic review of acute telogen effluvium, a harrowing post-COVID-19 manifestation. J Med Virol. 2022;94(4):1391-1401. doi: 10.1002/jmv.27534. PMID: 34931698.Verified on 2 October 2026
- 8.Mirallas O, Grimalt R. The Postpartum Telogen Effluvium Fallacy. Skin Appendage Disord. 2016;1(4):198-201. doi: 10.1159/000445385. PMID: 27386466.Verified on 2 October 2026
- 9.Asghar F, Shamim N, Farooque U, Sheikh H, Aqeel R. Telogen Effluvium: A Review of the Literature. Cureus. 2020;12(5):e8320. doi: 10.7759/cureus.8320. PMID: 32607303.Verified on 2 October 2026
Educational content. It does not replace a medical consultation or provide a diagnosis. Tests and treatments are indicated only after medical consultation and in line with regulation.