Most nail changes are harmless. A few are early warnings worth listening to. Here is the Heaven Care Clinic guide to the ten nail changes our podiatrists most often want to see — and exactly when to book your GP, your pharmacist, or us.
Your fingernails and toenails are quietly informative. The NHS lists nail changes as a recognised symptom of psoriasis, iron-deficiency anaemia, thyroid disorders, diabetes, and — less commonly — heart, lung or liver disease. Most of the time, a ridged or discoloured nail is nothing to worry about. But some nail changes deserve a closer look, and a small number need urgent attention.
Below are the ten we are asked about most often at our Bournemouth clinic — what each one looks like, what it may mean, and what to do next.
1. A new dark streak on one nail (longitudinal melanonychia)
What you’ll see: A single brown or black line running from the cuticle to the tip of one nail.
Why it matters: A new, widening or dark band on a single nail can — rarely — be an early sign of subungual melanoma, a melanoma that grows under the nail. The NHS specifically lists “a dark area under a nail that has not been caused by an injury” as a sign to get checked. Pigmented nails are common and usually benign in people with darker skin, but a new or changing band still deserves review.
What to do: Book an urgent GP review if the streak is new, widening, very dark, or if the pigment has spread onto the skin around the nail (the “Hutchinson sign”). Do not wait — early melanoma is highly treatable.
2. Clubbing — rounded, bulbous fingertips with curved nails
What you’ll see: Fingertips look swollen and the nails curve down over them, like the back of a spoon turned upside-down. There is a quick self-test (sometimes called the Schamroth window): press the nails of two opposite fingers together — a healthy pair leaves a small diamond-shaped gap, clubbed nails do not.
Why it matters: The NHS describes clubbing as a “sign of many serious, long-term conditions of the heart, lungs, liver and gut.” It is rarely sudden and almost always points to a systemic cause that needs investigation.
What to do: Book a routine GP appointment. Mention if there is a family history, a long-term cough, or breathlessness on exertion.
3. Spoon-shaped nails (koilonychia)
What you’ll see: Nails that dip inwards in the centre — flat or concave enough to hold a small drop of water.
Why it matters: The NHS lists “nail changes, such as spoon-shaped nails” as a less-common symptom of iron-deficiency anaemia. It can also follow long-term wet work, certain skin conditions, or thyroid problems.
What to do: GP review with a simple blood test (full blood count + ferritin) is the right first step.
4. Horizontal grooves across the nail (Beau’s lines)
What you’ll see: Side-to-side ridges or grooves that move up the nail as it grows. Often appear on more than one nail at once.
Why it matters: Beau’s lines mark a moment when nail growth was briefly interrupted — most commonly by a high fever, severe illness, chemotherapy, a tough COVID-19 infection, or sometimes a period of poor nutrition. They grow out as the nail grows up.
What to do: Usually no action needed. If they appear without any obvious illness, mention it to your GP.
5. The nail is lifting away from the bed (onycholysis)
What you’ll see: A pale or white area where the nail has separated from the pink nail bed — usually at the tip first, sometimes at the side.
Why it matters: DermNet lists the most common causes as repeated trauma (running shoes, manicures), fungal or candida infection, psoriasis, dermatitis, thyroid disease, and certain medications. Nail polish gels and acrylics are an under-recognised cause we see often in clinic.
What to do: Book a podiatry or GP appointment. The lifted portion will not reattach, but new nail growth will — provided the underlying cause is treated.
6. Pitted, rough or crumbling nails
What you’ll see: Tiny pinprick dents on the nail surface, or a crumbling edge. The NHS describes nail psoriasis as nails that “have dents and pits.”
Why it matters: Most often linked to psoriasis, eczema, or alopecia areata. Pitting is one of the earliest signs of psoriatic nail disease and can appear before any skin involvement.
What to do: Podiatry or GP review. If you have psoriasis elsewhere, mention the nail change at your next dermatology appointment.
7. Thick, yellow or brittle nails (often a fungal infection)
What you’ll see: Nails that look thicker than usual, with a yellow, white or brown discolouration. Often crumbly at the edge. Most common on the toenails, especially the big toe.
Why it matters: The NHS describes fungal nail infections as starting at the nail edge and progressing to make nails “white or yellow,” eventually “brittle and crumbly.” Risk is higher in trainers worn for long hours, people with diabetes, and anyone with a weakened immune system.
What to do: A pharmacist can help with mild cases. Book a podiatry appointment if more than one nail is affected, if you have diabetes, or if a topical treatment hasn’t worked after a few months — fungal testing may be needed before prescribing tablets, and we can do a clearing reduction in clinic to help any treatment reach the infection.
8. Brittle or splitting nails
What you’ll see: Nails that flake at the tip, split along the length, or break before they grow long.
Why it matters: Most often caused by ageing, frequent water exposure, harsh nail products, or repeated soak-off gels. Less commonly, it can reflect thyroid disease or a nutritional issue (low iron, biotin, or vitamin D).
What to do: Try the easy fixes first — cotton-lined washing-up gloves, a nourishing nail oil twice daily, a short break from gels. If brittleness persists for more than a few months or comes with fatigue, hair loss, or temperature intolerance, see your GP.
9. White lines or bands across the nails (Mees’ lines)
What you’ll see: One or more pale, horizontal bands stretching across the whole nail. They follow the curve of the cuticle and grow out with the nail.
Why it matters: Classically associated with severe systemic illness or with certain medications (including some chemotherapy agents). Single, scattered white spots (leukonychia) are usually a minor trauma to the nail matrix and not a concern.
What to do: GP review if multiple nails are affected and you cannot link the bands to a recent illness.
10. Blue, pale, or “half-and-half” nails
What you’ll see:
- Blue nails — bluish discolouration of the nail bed.
- Pale nails — the pink colour has drained away.
- Half-and-half nails — the lower half is white, the upper half is pink or brown.
Why it matters: Blue nails can indicate low blood oxygen. Pale nails can suggest anaemia. Half-and-half nails are sometimes associated with kidney disease.
What to do: Blue nails together with breathlessness need same-day medical assessment — call NHS 111 or go to your GP. Pale or half-and-half nails warrant a routine GP review with bloods.
When to contact a GP, a pharmacist or a podiatrist
A simple way to triage what you are seeing:
- Same-day medical advice (call NHS 111 or your GP): blue nails with breathlessness; signs of a spreading infection around the nail (pain, heat, pus).
- Routine GP appointment: a new dark streak, clubbing, spoon-shaped nails, multiple Beau’s lines without a clear cause, half-and-half nails, persistent brittleness with other symptoms.
- Pharmacist or podiatrist (us): suspected fungal infection, an ingrown or thickened toenail, painful corns or calluses, post-injury nail changes, recurring onycholysis from gels or running.
- Self-care: vertical ridges that have appeared gradually with age (very common, almost always harmless), the occasional white spot from a knock.
If you are unsure, book a podiatry appointment — most nail problems we see are quickly identifiable in clinic, and we can refer on to your GP with notes if a systemic cause is suspected.
Frequently asked questions
What does it mean when your nails change colour?
Nail colour reflects what is happening underneath. Yellow usually points to fungal infection or — rarely — long-term smoking; blue or pale can indicate circulation or oxygen issues; a single dark streak that is new or changing should be seen urgently. Single white spots from a knock are common and harmless.
Are vertical ridges on nails a sign of vitamin deficiency?
Most vertical ridges are a normal part of ageing, not a deficiency. Persistent, deep ridges in younger adults — especially with brittleness or fatigue — are worth a GP blood test (iron, ferritin, thyroid).
How can I tell the difference between a fungal nail and a nail melanoma?
Fungal nails usually start at the edge, affect more than one nail, and are thick, crumbly and yellow-brown. A melanoma is more often a single, narrow dark band on one nail that gets wider or darker over time. If in doubt, get it checked — the cost of being wrong is high.
Will damaged nails grow back to normal?
Usually yes, but slowly. Fingernails take around six months to grow out fully; toenails can take up to eighteen months. The key is identifying and treating the cause so the new growth comes through healthy.
Should I stop wearing nail polish if I have a nail problem?
For investigation and treatment — yes, at least temporarily. Polish (especially gels and acrylics) can hide colour changes, prevent topical antifungals working, and prolong onycholysis. Take a break, treat the cause, and your nails will thank you.
Book a nail health check at Heaven Care Clinic
If you have noticed a nail change that does not look like any of the everyday culprits — or if you are simply not sure — bring it to us. Our HCPC-registered podiatrists in Winton, Bournemouth see nail problems every day. We will take a careful look, treat what we can in clinic, and tell you honestly when something is best handled by your GP.
Book online at heavencareclinic.co.uk — or call the clinic and we’ll find you a slot this week.
References
- NHS, Nail problems — https://www.nhs.uk/conditions/nail-problems/
- NHS, Iron deficiency anaemia — Symptoms — https://www.nhs.uk/conditions/iron-deficiency-anaemia/
- NHS, Fungal nail infection — https://www.nhs.uk/conditions/fungal-nail-infection/
- NHS, Psoriasis — Symptoms — https://www.nhs.uk/conditions/psoriasis/symptoms/
- NHS, Melanoma skin cancer — Symptoms — https://www.nhs.uk/conditions/melanoma-skin-cancer/symptoms/
- DermNet NZ, Melanonychia — https://dermnetnz.org/topics/melanonychia
- DermNet NZ, Onycholysis — https://dermnetnz.org/topics/onycholysis
This article is general information and not a clinical diagnosis. If you are worried about a nail change, please see your GP, an HCPC-registered podiatrist, or call NHS 111.