Nails
Brittle or changing nails
Nails that split, peel, ridge, crumble or change colour and shape — often simply from age, water exposure or minor damage, but sometimes a sign of iron deficiency, an underactive thyroid or a skin condition, and occasionally, when a dark streak appears, something that must be checked.
Education and reference only. This explains the common causes of brittle or changing nails 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 brittle or changing nails?
Nails are made of layers of a tough protein and grow slowly, so changes in their strength, texture or appearance build up over weeks to months and often reflect what has been happening to the body or the nails over that time. Brittle nails that split, peel or break easily are very common and frequently come from everyday causes — repeated wetting and drying, harsh soaps, nail products, cold weather or simply ageing.
- Get urgent help: See your doctor promptly about a new dark streak or a changing brown-to-black band running along a nail — this can rarely signal a melanoma and needs checking. Get urgent help if the skin around a nail becomes hot, red, swollen, throbbing or oozing pus, which suggests infection.
- Self-care: Brittle nails usually strengthen with patience and gentle care, as new healthy nail takes months to grow out.
About brittle or changing nails
Nails are made of layers of a tough protein and grow slowly, so changes in their strength, texture or appearance build up over weeks to months and often reflect what has been happening to the body or the nails over that time. Brittle nails that split, peel or break easily are very common and frequently come from everyday causes — repeated wetting and drying, harsh soaps, nail products, cold weather or simply ageing. Sometimes, though, nail changes signal an internal cause: iron deficiency can make nails thin and spoon-shaped, an underactive thyroid can leave them brittle, and skin conditions such as psoriasis cause pitting and lifting. Fungal infection thickens and discolours nails over time. Most nail changes are harmless and slow to reverse, but one change always needs attention: a new dark streak or a changing pigmented band running along a nail, which can rarely be a sign of skin cancer.
When to get help
Call 999 or go to A&E if brittle or changing nails comes with any of these warning signs:
- See your doctor promptly about a new dark streak or a changing brown-to-black band running along a nail — this can rarely signal a melanoma and needs checking.
- Get urgent help if the skin around a nail becomes hot, red, swollen, throbbing or oozing pus, which suggests infection.
- See your doctor if a nail lifts off, changes shape or colour quickly, or if several nails change together with feeling generally unwell.
- Seek advice for finger clubbing — where the nails curve and the fingertips broaden — particularly with breathlessness or a cough.
- See your doctor if brittle nails come with tiredness, pallor, feeling the cold or hair changes, as iron or thyroid problems may be the cause.
When to see a doctor
Most brittle and changing nails are harmless and improve slowly with protection and gentle care, so they do not usually need a doctor. Book a routine appointment if nail changes are widespread, come on with other symptoms such as tiredness, pallor or feeling the cold, or look like a fungal infection that is spreading, so the cause can be confirmed. Seek prompt advice — and do not delay — for any new dark streak or changing pigmented band under or along a nail, as this is the one nail change that must always be examined directly. Get urgent help if the skin around a nail becomes hot, red and swollen with pus.
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 brittle or changing nails
Brittle or changing nails 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
Brittle nails usually strengthen with patience and gentle care, as new healthy nail takes months to grow out. Protect them from repeated wetting and harsh chemicals by wearing gloves for washing-up and cleaning, and moisturise the nails and the skin around them regularly, especially after washing. Keep nails trimmed fairly short and filed smooth to reduce snagging and splitting, and go easy on nail varnish removers and artificial nails, which can dry and weaken the nail. A balanced diet supports healthy nails. Avoid biting or picking at the nails and the surrounding skin. If nails are crumbling, discoloured or thickened in a way that looks like infection, a pharmacist can advise; and never ignore a new dark line under a nail — have it looked at.
Answers
Brittle or changing nails: frequently asked questions
What causes brittle, splitting nails?
Most often it is everyday wear — repeated wetting and drying, harsh soaps, nail products, cold weather and ageing. Sometimes iron deficiency, an underactive thyroid or a skin condition is behind it, particularly if other symptoms are present.
When should I worry about a nail change?
A new dark streak or a changing pigmented band along a nail should always be checked promptly, as it can rarely indicate skin cancer. Sudden changes in shape or colour, several nails changing together, or signs of infection also warrant a doctor.
Can a vitamin or iron problem affect my nails?
Yes. Iron deficiency can make nails thin and spoon-shaped, and an underactive thyroid can make them brittle. If nail changes come with tiredness, pallor or feeling the cold, ask your doctor whether a blood test is worthwhile.
How long do nails take to recover?
Nails grow slowly, so it can take several months for a fingernail and longer for a toenail to grow out and replace damaged nail. Consistent protection and moisturising help, but improvement is gradual rather than quick.
Sources
Where this is drawn from
- NICE CKS: Nail problems.
- British Association of Dermatologists: nail conditions.
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