Skin
Hair loss
Thinning or shedding of hair on the scalp or body that is most often a natural, gradual pattern of balding but can also follow stress, illness or hormonal changes, or signal a thyroid problem, low iron or a scalp condition that needs early treatment.
Education and reference only. This explains the common causes of hair loss and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is hair loss?
Hair loss takes many forms, and recognising the pattern helps point to the cause. The commonest is gradual pattern thinning, an inherited tendency that recedes the hairline or thins the crown over years.
- Get urgent help: See a doctor promptly for hair loss with a scaly, scarring or painful scalp — scarring hair loss can become permanent if not treated early. See a doctor promptly for sudden patchy hair loss that is spreading quickly.
- Self-care: Looking after your hair gently can limit further loss while the cause is sorted out.
About hair loss
Hair loss takes many forms, and recognising the pattern helps point to the cause. The commonest is gradual pattern thinning, an inherited tendency that recedes the hairline or thins the crown over years. Sudden, patchy bald spots with smooth skin suggest alopecia areata, where the immune system attacks the hair follicles, while diffuse shedding a few months after childbirth, a serious illness, an operation or major stress is usually temporary and recovers. Some hair loss reflects a treatable medical cause, such as an under- or over-active thyroid, a shortage of iron, or a hormonal condition like polycystic ovary syndrome. A scaly, itchy or painful scalp can indicate a fungal infection or a scarring condition. The key distinction is between non-scarring hair loss, where the follicles survive and regrowth is possible, and scarring hair loss, which can be permanent if not treated early.
When to get help
Call 999 or go to A&E if hair loss comes with any of these warning signs:
- See a doctor promptly for hair loss with a scaly, scarring or painful scalp — scarring hair loss can become permanent if not treated early.
- See a doctor promptly for sudden patchy hair loss that is spreading quickly.
- See a doctor for hair loss alongside tiredness, weight change or very heavy periods, as these may need investigation.
- Seek advice for hair loss with broken hairs, redness or pus on the scalp, which can mean an infection.
- See a doctor if hair loss is rapid, total, or causing significant distress.
When to see a doctor
Some thinning with age is normal and may not need a doctor, but it is worth seeking advice if hair loss comes on suddenly, appears in patches, spreads quickly, or comes with a sore, scaly or scarring scalp that could leave permanent loss if left. You should also see a doctor if hair loss is accompanied by other symptoms such as tiredness, weight change, very heavy periods or unwanted hair growth, as these may point to a treatable cause that a blood test can identify. Early assessment matters most for any scarring or rapidly spreading loss.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of hair loss
Hair loss has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
Looking after your hair gently can limit further loss while the cause is sorted out. Avoid tight hairstyles, harsh brushing, hot styling tools and aggressive chemical treatments that stress the hair shaft. Eat a balanced diet with enough protein and iron-rich foods, as deficiencies can worsen shedding, and manage stress, which is a common trigger for temporary loss. If thinning is affecting your confidence, gentle styling, a different parting or, for some, a wig or hairpiece can help while you wait for regrowth or treatment. Temporary shedding after illness, childbirth or stress usually recovers over several months once the trigger has passed, so patience is often part of the answer.
Answers
Hair loss: frequently asked questions
Is some hair loss normal?
Yes. It is normal to shed a number of hairs each day, and gradual thinning with age is common. Hair loss becomes worth checking when it is sudden, patchy, rapid, or comes with a sore or scaly scalp or other symptoms such as tiredness or weight change.
Will my hair grow back?
It depends on the cause. Temporary shedding after illness, stress or childbirth, and patches from alopecia areata, often regrow because the follicles survive. Scarring hair loss can be permanent, which is why a sore or scarring scalp should be seen early.
Can stress cause hair loss?
Yes. Major physical or emotional stress, a serious illness, an operation or childbirth can trigger increased shedding a few months later. This type of loss is usually temporary and recovers over several months once the trigger has passed.
Could my hair loss mean a thyroid or iron problem?
It can. Both an underactive thyroid and a shortage of iron can cause diffuse thinning, often with tiredness and other symptoms. A simple blood test can check for these, so hair loss with tiredness or other changes is worth discussing with a doctor.
Sources
Where this is drawn from
- NICE CKS: Hair loss in adults.
- Alopecia UK: types of hair loss.
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