Have you noticed your hair suddenly becoming thinner or shedding more than usual? You may be experiencing telogen effluvium, also known as telogen alopecia. This is a temporary form of hair loss where many hairs enter the resting phase of the growth cycle at the same time, often triggered by stress, hormonal changes or illness. In this article, we’ll explain what telogen effluvium is, what the main causes are and how long telogen effluvium typically lasts.
What is telogen effluvium?
Telogen effluvium is a temporary form of diffuse hair loss, which means the hair thins evenly across the entire scalp. This is different from androgenetic alopecia (hereditary hair loss), where hair loss follows a clear pattern such as a receding hairline or thinning crown.
In telogen effluvium (also known as telogen hair loss or telogen alopecia), a large number of hairs prematurely enter the telogen, or resting, phase of the hair growth cycle. Your hair naturally goes through a continuous cycle consisting of three phases: the growth phase (anagen), the transition phase (catagen) and the resting phase (telogen). During the resting phase, hair temporarily stops growing before eventually shedding. When too many hairs enter this phase at once, you may notice sudden, excessive hair shedding.
Difference between Telogen Effluvium and Androgenetic Alopecia
Androgenetic alopecia is another common form of hair loss, but quite different from telogen effluvium. In telogen effluvium, the hair loss is temporary: the follicles remain healthy and can grow new hairs again.
In androgenetic alopecia, however, the follicles gradually shrink, leading to thinner regrowth and eventually permanent hair loss. That’s the key difference between the two conditions.
Telogen Effluvium disrupts the hair growth cycle
As mentioned earlier, your hair doesn’t grow continuously but in phases, known as the hair growth cycle:
- Growth phase (anagen) – Hair grows actively, lasting several years.
- Transition phase (catagen) – Hair stops growing and prepares to shed, lasting a few weeks.
- Resting phase (telogen) – The hair sheds, and a new cycle begin
Normally, we lose about 50 to 100 hairs a day. In telogen effluvium, many more hairs than usual enter the resting phase, disrupting the normal growth cycle and causing visible thinning.
Causes of Telogen Effluvium
What causes telogen effluvium? It can have several different triggers. Common causes include:
- Stress – for example, following surgery, illness or emotional strain.
- Hormonal changes – such as after giving birth, changing contraception or during menopause.
- Pregnancy – temporary hair shedding a few months after childbirth is common.
- Nutritional deficiencies – such as low iron, vitamin D or protein intake.
- Illness – including infections or thyroid problems.
- Medications – certain medicines can temporarily cause increased hair shedding.
Sometimes, none of these causes apply to you personally. If you’re experiencing diffuse hair loss and are unsure why, it’s best to consult your general practitioner or dermatologist for assessment and reassurance.
How to recognise Telogen Effluvium
With telogen effluvium, you’ll notice that your hair becomes thinner across your entire scalp. This is known as diffuse hair loss. Instead of bald patches, your hair looks less full all over.
Many people only notice it when their hair starts losing volume or when more hair falls out during washing, brushing or styling. You might see extra hair on your pillow, in the shower drain or on your clothes.
The hairs that fall out usually look healthy, they don’t break but come out completely, often with a small white bulb at the end. This bulb isn’t the root but simply the end of a hair that has completed its resting phase.
Other common signs
- Your parting appears wider, or more scalp is visible through your hair.
- Your hair feels lighter or less dense, especially on top of the head.
- The scalp may feel more sensitive or tender, though there are no sores or flakes.
These are typical signs of telogen effluvium. Because the follicles remain intact, the hair loss is almost always temporary. Once the hair growth cycle resets, new hair gradually grows back.
How long does Telogen Effluvium last?
The good news is that telogen effluvium is usually temporary. Hair growth often returns to normal within 6 to 12 months, once the underlying cause is resolved and your body has recovered.
It can take time before you see visible regrowth, as hair only grows about 1 cm per month on average. Some people recover faster, others more slowly: this depends on your overall health and what caused the shedding in the first place.
There are two main types of telogen effluvium: acute and chronic.
Acute Telogen Effluvium
In the acute form, many hairs enter the resting phase too soon. This can happen after a stressful period, hormonal change or thyroid imbalance. During recovery, the body temporarily focuses on vital functions, so hair growth becomes less active.
Hair shedding typically begins two to five months after the triggering event. This delay can be confusing, the stress or illness is already over, yet the hair loss begins later. Fortunately, in most cases, hair growth returns to normal once your body is back in balance.
Chronic Telogen Effluvium
If hair shedding continues for longer than six months, it’s called chronic telogen effluvium. This condition is less common and can be emotionally challenging. Sometimes there is an identifiable cause, but in about 30% of cases, no clear reason is found.
Possible contributing factors include:
- Nutrient deficiencies, such as low iron, biotin, selenium or protein.
- Hormonal changes, for example thyroid disorders or menopause.
- Long-term illnesses, including liver or kidney problems.
- Chronic skin conditions, such as eczema or psoriasis.
- Medications or supplements that may list hair loss as a side effect.
When to seek medical advice
Telogen effluvium usually resolves on its own. However, it’s important not to ignore persistent symptoms. Speak to your general practitioner or dermatologist if:
- Hair loss is severe or lasts longer than a year.
- You’re unsure whether it might be another form of hair loss.
- You have other symptoms such as scalp pain, redness or sudden bald patches.
A doctor can examine your scalp, discuss possible causes and, if necessary, arrange blood tests to check for issues such as thyroid imbalance or nutrient deficiencies.
Conclusion
Telogen effluvium is a temporary form of diffuse hair loss where hair thins evenly across the scalp. It usually follows a period of stress, hormonal change, illness or medication use. Because the hair follicles remain healthy, the shedding is reversible: once the growth cycle rebalances, new hair naturally regrows.
For most people, shedding stops within 6 to 12 months. It might take time to see improvement, hair grows slowly, around 1 cm per month, but permanent baldness is rare.
If you’re worried or the hair loss persists, consult your general practitioner or dermatologist. They can identify the cause and offer reassurance. The most important thing to remember is that telogen effluvium is usually temporary and self-correcting. With patience, rest and proper nutrition, your hair will likely return to its normal growth rhythm.
Frequently Asked Questions About Telogen Effluvium
What’s the difference between diffuse hair loss and telogen effluvium?
Diffuse hair loss means hair thins evenly across the scalp rather than in distinct patches. Telogen effluvium is the most common cause of diffuse hair loss, where many hairs enter the resting phase simultaneously, leading to temporary shedding.
Can telogen effluvium return?
Yes, it can recur if the triggering factor happens again. In chronic telogen effluvium, the shedding lasts longer than six months.
How is telogen effluvium diagnosed?
A doctor will discuss your symptoms and examine your hair. Sometimes, a gentle “pull test” is done to see how many hairs come loose. Blood tests may also be recommended to rule out underlying conditions or nutrient deficiencies.
References
Harrison S, Sinclair R. Telogen effluvium. Clin Exp Dermatol. 2002;27(5):389–395.
Malkud S. Telogen Effluvium: A Review. J Clin Diagn Res. 2015;9(9):WE01–WE03.
