Nail problems
Nails record what is happening in the body: they grow slowly and hold the trace of an illness, a deficiency or a medicine for months.
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Medicines commonly prescribed for Nail problems
For informational purposes only. Always consult a doctor before taking any medication.
Dosage form: SHAMPOO, 15 mg/gActive substance: ciclopiroxManufacturer: Qualix Pharma S.L.Prescription requiredDosage form: NAIL POLISH, 80 mg/gActive substance: ciclopiroxManufacturer: Isdin S.A.Prescription requiredDosage form: SHAMPOO, 15 mg/gActive substance: ciclopiroxManufacturer: Isdin S.A.Prescription required
Nails record what is happening in the body: they grow slowly and hold the trace of an illness, a deficiency or a medicine for months. Many changes are harmless, others indicate a skin or internal condition, and a few are signals not to overlook. This article helps place what you are seeing in the right group.
Changes in colour
- white nails: pinpoint spots from minor trauma, very common and harmless. If the whole nail is whitish, there may be liver disease or low blood albumin;
- yellow nails: fungal infection, psoriasis, smoking, dark polish worn without breaks; with thickening and respiratory problems, yellow nail syndrome;
- blue nails: lack of oxygen, circulatory problems, some medicines;
- half white and half brown: associated with kidney disease;
- splinter haemorrhages: fine reddish lines; almost always from trauma, but if they are multiple and there is fever, endocarditis must be excluded;
- subungual haematoma: after a knock, a dark mark that grows out with the nail and moves towards the free edge.
The signal not to ignore
A dark longitudinal band in a single nail, particularly if it is widening, changing colour or the pigment is spreading onto the skin around the nail, must be assessed to exclude nail melanoma. It is often diagnosed late because it is put down to a knock nobody remembers. A haematoma moves towards the free edge; a band of pigment produced by melanocytes does not.
Changes in shape and surface
- transverse grooves (Beau's lines): they reflect a pause in growth caused by illness, high fever, surgery or chemotherapy some months earlier;
- longitudinal ridges: common with age and harmless;
- spoon-shaped nails, concave: classic for iron deficiency;
- clubbing, watch-glass nails with broadened fingertips: associated with lung, heart or digestive conditions and warranting investigation;
- pitting, small dents in the surface: typical of psoriasis, also of eczema and alopecia areata;
- onycholysis, the nail lifting from its bed: from trauma, psoriasis, fungal infection, excessive moisture, aggressive manicure or medication;
- brittle nails that peel in layers: from water, detergents, acetone removers and sometimes deficiencies.
Problems with the surrounding skin
- acute paronychia: redness, pain and pus beside the nail edge, after an injury or from cutting the cuticle;
- chronic paronychia: persistent swelling without pus, typical in people whose hands are often wet; the cuticle is lost and the nail grows ridged;
- ingrown toenail;
- periungual warts.
When to see a doctor
- there is a dark band in a single nail, or pigment on the surrounding skin;
- one nail is progressively changing shape without any injury;
- there is pain, swelling, redness or pus;
- the nail is lifting or deforming;
- several nails are thickened and discoloured;
- there is pitting alongside skin lesions: this may be psoriasis;
- nails have become markedly concave or brittle;
- the fingertips have broadened;
- there is bleeding under a nail with no injury;
- you have diabetes or circulatory problems and something about your nails has changed.
How it is assessed
Examination with a dermatoscope; a nail scraping or clipping for microscopy and culture if fungal infection is suspected — and this is worth confirming before months of oral treatment; blood tests including full blood count, ferritin, liver, kidney and thyroid function depending on the case; and a nail matrix biopsy where a pigmented band is suspicious.
Nail care
- cut them straight across, without rounding the corners on the toes;
- gloves for wet work and for cleaning products;
- moisturise nails and cuticles daily;
- do not cut the cuticle: it is the barrier protecting the matrix; gently pushing it back is enough;
- avoid acetone removers and file in one direction only;
- take breaks between gel manicures and avoid aggressive buffing of the surface;
- use your own manicure tools or ensure they are sterilised;
- do not use your nails as tools;
- footwear with enough room for the toes;
- dry hands and feet thoroughly.
Common questions
Are white spots a calcium deficiency? No. They are almost always minor trauma to the matrix.
How long does a nail take to grow? Fingernails, 4–6 months; toenails, 9–12. That is why any treatment is judged in months.
Do supplements help? Only if there is a deficiency. Biotin has limited evidence and also interferes with some blood tests.
Will a torn-off nail grow back? Yes, unless the matrix has been damaged.
Do gel manicures ruin nails? The product itself less so; the damage comes from the buffing beforehand and from peeling it off.
Online consultation
In an online consultation the doctor reviews photographs of your nails, distinguishes a harmless change from one needing investigation, pays specific attention to pigmented bands, advises whether a fungal infection should be confirmed before treating, and sets out the care that prevents most of these problems.
This material is for information only and does not replace a medical consultation.
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Medically reviewed by
Reviewed on Jul 7, 2026
Online doctors for Nail problems
Discuss your symptoms and possible next steps for Nail problems with a doctor online.
