Acute Telogen Effluvium

What is Acute Telogen Effluvium?

Acute telogen effluvium is a form of temporary hair loss that occurs when a large number of hair follicles shift from the growth phase into the resting (telogen) phase at once. This sudden shift is usually triggered by a significant event or stressor affecting the body, such as illness, surgery, or emotional distress. The result is a noticeable increase in hair shedding, often seen as hair coming out in larger amounts during washing or brushing.

Unlike some other types of hair loss, acute telogen effluvium does not cause scarring or permanent damage to the hair follicles. Most people experience a return to normal hair growth once the underlying trigger is resolved. In fact, about 95% of cases resolve on their own within a few months. Acute telogen effluvium is different from chronic telogen effluvium, which lasts longer than six months and may not have a clear cause.

How Hair Grows and Sheds

Understanding the hair growth cycle helps explain why acute telogen effluvium leads to sudden hair shedding. Hair follicles cycle through three main phases: anagen (growth), catagen (transition), and telogen (resting/shedding). At any given time, about 80% to 90% of scalp hairs are in the anagen phase, actively growing for up to four years. The catagen phase is a brief transition, while the telogen phase is when hair rests and eventually sheds.

In telogen effluvium, a stressor causes a larger proportion of hairs-sometimes up to 70%-to abruptly enter the telogen phase. Normally, only around 5% to 15% of hairs are in this phase. This shift results in increased shedding, often noticed two to three months after the triggering event.

What Causes Acute Telogen Effluvium?

Common Trigger Events

Acute telogen effluvium is almost always set off by a specific trigger event that disrupts the normal hair cycle. These triggers can include acute illnesses with high fever, major surgery, severe infections, childbirth, sudden weight loss, crash dieting, or significant emotional stress. The body responds to these events by shifting hair follicles into the resting phase, conserving resources for essential functions.

Medications are another common cause. Beta-blockers, retinoids (including excess vitamin A), anticoagulants, and certain anticonvulsants have all been linked to acute telogen effluvium. Stopping estrogen-containing medications or experiencing hormonal changes, such as those after childbirth, can also trigger shedding.

Examples of Stress and Illness

Physical stressors like major trauma, surgery, or a serious infection can prompt acute telogen effluvium. Even a high fever or a severe flu can be enough to disrupt the hair cycle. Nutritional deficiencies, especially low iron or protein intake, and rapid changes in diet are also recognized triggers.

Emotional stress plays a significant role as well. Events such as bereavement, job loss, or significant life changes can lead to sudden hair shedding. The body’s response to stress involves hormonal and immune system changes that can impact hair growth.

Signs and Symptoms of Acute Shedding

The hallmark symptom of acute telogen effluvium is sudden, diffuse hair shedding. People often notice more hair on their pillow, in the shower drain, or on their hairbrush. Shedding can be dramatic, with up to 300 hairs lost per day compared to the usual 50 to 100. The hair loss typically affects the entire scalp but is most noticeable on the top of the head.

Despite the amount of hair lost, acute telogen effluvium rarely leads to complete baldness or a receding hairline. The hair may appear thinner overall, but the scalp is usually not patchy. In rare cases, other body hair such as eyebrows may be affected. The condition does not cause pain, itching, or redness, but the psychological impact can be significant, leading to anxiety or distress.

Timeline: What to Expect

Onset

Hair shedding from acute telogen effluvium typically begins two to three months after the triggering event. This delay is due to the natural timing of the hair growth cycle. For example, if someone experiences a high fever or major surgery, increased hair loss may not be noticed until several weeks later.

The onset can feel sudden and alarming, especially if large amounts of hair come out during washing or brushing. Recognizing the timing of the trigger event is key to understanding and managing the condition.

Duration

The active shedding phase of acute telogen effluvium usually lasts less than six months. Most people notice the most intense shedding for several weeks to a few months. As the body recovers from the initial trigger, the hair cycle gradually returns to normal.

If shedding continues beyond six months, the condition may be considered chronic telogen effluvium. In most cases, however, the shedding slows and stops as new hair growth begins. For more information on chronic forms, see Chronic Telogen Effluvium.

Recovery and Regrowth

Recovery from acute telogen effluvium is the rule rather than the exception. About 95% of people experience full regrowth once the underlying cause is addressed. New hairs start to grow as follicles re-enter the anagen (growth) phase, but it can take several months for noticeable improvement.

Hair grows at a rate of about 0.25 to 0.5 inches per month, so regaining previous fullness may take up to a year or more. Patience and supportive care are important during this time.

Who is Affected?

Acute telogen effluvium can affect anyone, regardless of age, gender, or ethnicity. It is one of the most common causes of rapid hair loss and is especially prevalent among women, partly due to hormonal changes related to pregnancy and childbirth.

While both men and women can experience acute telogen effluvium, women are more likely to seek medical attention for hair shedding. The condition is not limited to any specific age group, and many adults will experience at least one episode in their lifetime.

How is Acute Telogen Effluvium Diagnosed?

Diagnosis of acute telogen effluvium is based on a detailed history and physical examination. Healthcare providers will ask about recent illnesses, surgeries, major life events, medications, and dietary changes in the months before the onset of shedding. The pattern of hair loss-diffuse thinning without patchiness-helps distinguish it from other types of hair loss.

A “hair pull test” may be performed, where a small group of hairs is gently pulled to see how many come out. If more than 10% of the hairs are easily pulled, this suggests active shedding. In some cases, additional tests such as blood work (to check for nutritional deficiencies or thyroid issues) or a scalp biopsy may be recommended if the diagnosis is unclear or if hair loss persists.

Treatment and Self-care Tips

Most cases of acute telogen effluvium resolve without medical treatment once the underlying trigger is addressed. The most important step is to identify and manage the cause, whether it is a recent illness, medication, or significant stress. Reassurance and patience are key, as the hair cycle takes time to normalize.

Supportive self-care can help promote hair regrowth and overall scalp health. This includes eating a balanced diet rich in protein, iron, vitamins, and essential fatty acids. Over-the-counter topical minoxidil may be considered in some cases to support regrowth. Managing stress through relaxation techniques, exercise, and adequate sleep can also be beneficial.

Preventing Future Episodes

While not all cases of acute telogen effluvium can be prevented, certain lifestyle habits can reduce the risk of future episodes. Maintaining a healthy, balanced diet with adequate iron, vitamins, and protein supports the body’s resilience to stressors. Avoiding crash diets and sudden weight loss is especially important.

Managing stress through mindfulness, regular exercise, and sufficient sleep can help protect the hair cycle. If you experience a major life event or illness, being aware of the potential for temporary hair shedding can help you prepare and seek support if needed.

Frequently Asked Questions (FAQ)

Is acute telogen effluvium permanent?

No, acute telogen effluvium is almost always temporary. About 95% of cases resolve on their own once the underlying trigger is addressed, and hair regrowth typically follows.

How long does shedding last?

Shedding from acute telogen effluvium usually lasts less than six months. Most people notice the most intense shedding for several weeks to a few months before it slows and stops.

Can stress alone cause sudden hair shedding?

Yes, significant emotional or physical stress can trigger acute telogen effluvium. The body’s response to stress can disrupt the hair growth cycle, leading to increased shedding.

Will hair grow back on its own?

In most cases, hair regrows naturally as the follicles return to the growth phase. Full recovery is expected for the vast majority of people, although it may take several months for noticeable regrowth.

Should I change my hair care routine?

Gentle hair care is recommended during periods of shedding. Avoid harsh treatments or excessive heat styling. Focus on a balanced diet and scalp health to support recovery.

Are there any medical tests needed?

Basic blood tests may be recommended to check for nutritional deficiencies or thyroid problems if the cause is unclear. A hair pull test or scalp examination can help confirm the diagnosis.

Does diet influence recovery?

Yes, a nutritious diet with adequate protein, iron, and vitamins supports healthy hair regrowth. Addressing any deficiencies can help speed recovery.

Is medication needed for everyone?

Most people do not need medication for acute telogen effluvium. Treatment focuses on removing the trigger and supporting overall health. Topical minoxidil may be considered in some cases.