Anagen Effluvium

Overview

Anagen effluvium is a type of sudden hair loss that happens when something damages hair follicles while they are in their active growth phase. It usually affects the entire scalp, causing hair to fall out in large amounts within a few days or weeks. It is most often linked to cancer treatments like chemotherapy, but can also happen after radiation to the head or exposure to certain toxic chemicals.

Anagen effluvium is not common in the general population, but it is a well-known side effect of chemotherapy. It is most often seen in people who are receiving certain cancer treatments or who have been exposed to specific chemicals.

It can affect both children and adults of any gender. People undergoing chemotherapy or radiation to the head are most likely to experience it, as are people exposed to certain industrial chemicals or medications that stop cell growth.

Symptoms

Common symptoms

• Rapid, noticeable hair loss on the scalp, often coming out in clumps
• Thinning over the whole scalp within days or weeks
• Hair shedding easily when brushed or washed
• A tender or itchy scalp before or during hair loss

Symptoms in children

• Children may lose hair very quickly, which can be upsetting.
• Some children may complain of scalp discomfort or tingling before the hair falls out.

Symptoms in older adults

• Older adults may also lose hair on other parts of the body, such as eyebrows or body hair.
• Hair regrowth after the cause is stopped may be slower or thinner than before.

Causes

Main causes

• Chemotherapy drugs that target rapidly dividing cells, including hair follicle cells
• Radiation therapy to the head or neck
• Exposure to certain toxic chemicals or heavy metals
• Taking certain medications that interfere with cell division (like some immunosuppressants)

Risk factors

• Currently undergoing chemotherapy or radiation to the head
• Occupational exposure to industrial chemicals or radiation
• Taking medications that block cell growth for cancer or autoimmune conditions
• Having had recent hair loss from another cause, which may make the effect more noticeable

When to see a doctor

See a doctor urgently if:

• If you have breathing trouble, swelling of the face or throat, or chest pain — call emergency services immediately.
• If you are on chemotherapy and develop a fever or feel very unwell, seek urgent medical care.
• If your scalp becomes painful, red, or weeps fluid, contact your care team the same day.

Book a routine appointment if:

• If you notice sudden or excessive hair loss and are not sure why, book an appointment with your GP or specialist.
• If you are about to start a treatment that may cause hair loss, talk to your doctor beforehand so you can prepare.
• If your hair does not seem to regrow after treatment ends, follow up with your doctor.

Diagnosis

A doctor, often a GP, dermatologist, or your cancer team, usually diagnoses anagen effluvium by talking to you about your recent medical history and examining your scalp. If you are having chemotherapy, the pattern of hair loss is often enough to recognise what is causing it.

Tests that may be done

• A gentle pull test — the doctor gently pulls a small section of hair to see how many hairs come out easily.
• Microscopic examination of a few hairs to check the hair roots.
• Blood tests to rule out other causes of hair loss, such as thyroid or nutritional problems.
• A skin biopsy (taking a tiny sample of the scalp) is rarely needed, but may be done if the diagnosis is unclear.

What to expect at your appointment

The appointment is simple and painless. Your doctor will ask about your recent medications, treatments, and any other health changes. They may gently touch or examine your scalp. You might be referred to a dermatologist or to a specialist hair clinic for further advice. Do not worry if you have already lost a lot of hair — this does not affect the diagnosis.

Treatment

There is no treatment that directly stops anagen effluvium. The only truly effective approach is to remove or treat the underlying cause, such as waiting for chemotherapy to finish or eliminating exposure to a harmful chemical. In the meantime, the focus is on gentle hair care, protecting the scalp, and using cosmetic or supportive measures to cope with the hair loss.

Self-care at home

• Be very gentle with your hair. Use a soft shampoo, wide-tooth comb, and pat your hair dry rather than rubbing it.
• Avoid tight hairstyles, braids, buns, or anything that pulls on the hair.
• Do not use hair dyes, bleaches, perms, or harsh styling tools while hair is shedding.
• Protect your scalp from the sun with a hat, scarf, or sunscreen.
• Consider using a wig, hairpiece, scarf, or hat — many people find it helpful to choose a wig before hair loss begins.

Medical treatments

There are no specific medicines approved for anagen effluvium. Some doctors may discuss topical treatments that are sometimes used for other types of hair loss, but their benefit here is not well proven. You should always ask your doctor or pharmacist before using any product, including over-the-counter or herbal remedies. In some hospital settings, scalp cooling caps may be offered during chemotherapy to reduce hair loss — this is not a treatment, but a prevention measure.

When is surgery considered?

Surgery has no role in treating anagen effluvium.

Living with this condition

Hair loss can happen suddenly, so preparing early can make it easier. If you are about to start chemotherapy, ask your oncology team about what to expect. Keep a soft hat or scarf near your bed, and be ready for shed hair on pillows or in the shower. You may also want to get a wig before your hair falls out, so it matches your hair more closely.

Lifestyle tips

• Wear a sun hat or scarf to protect your scalp from direct sunlight.
• Keep your scalp moisturized with a gentle, fragrance-free lotion if it feels dry.
• Avoid extreme heat from hair dryers, straighteners, or curlers.
• If you are using a wig, make sure it fits comfortably and is cleaned regularly.
• Talk to your care team about whether scalp cooling is an option for you.

Diet and exercise

A balanced diet with adequate protein, iron, and vitamins supports your body during treatment and may help hair regrow. Gentle exercise, such as walking or stretching, can improve your mood and energy level, but always check with your doctor about what is safe for your situation. Stay well hydrated.

Mental health and emotional wellbeing

Losing your hair can feel like losing part of your identity. It is completely normal to feel sad, anxious, embarrassed, or even angry. These feelings are valid. If you feel overwhelmed, helpless, or unable to cope, please talk to your doctor, nurse, or a mental health professional. You do not have to go through this alone.

Prevention

Anagen effluvium is not usually preventable if it is a side effect of essential medical treatment. However, some people having chemotherapy may be able to reduce hair loss using scalp cooling caps — ask your oncology team if this is available and suitable for you. For occupational chemical exposure, using proper protective equipment and following safety guidelines can help. Once the trigger is removed, the hair loss stops on its own.

Vaccines

There are no vaccines to prevent anagen effluvium.

Screening programmes

There is no screening test for anagen effluvium. It is usually noticed by the person themselves and confirmed by a doctor.

Complications

If left untreated

• If the underlying cause continues (such as ongoing chemotherapy or toxic exposure), hair loss will continue and may become permanent in some cases.
• Bare scalp can get sunburned, dry, or irritated if it is not protected.
• Psychological distress, low self-esteem, and social anxiety are common without adequate support.
• In rare cases, the hair follicles can be permanently damaged if the harmful exposure is very severe or prolonged.

Long-term outlook

The good news is that for most people, anagen effluvium is temporary. Once the cause is removed — usually after chemotherapy or radiation finishes — hair typically begins to regrow within a few weeks or months. For many, hair returns completely, although it may initially come back thinner, finer, or a different colour. In some cases, regrowth takes longer, but with patience and support, most people adapt well. Talk to your healthcare team about what you can expect, and do not hesitate to seek emotional support if you need it.

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