Your nails can tell you lots about your health – here's what you need to know and what you can do about it

Healthy nails

Our fingernails grow at around 3mm a month, but toenails can take up to a year to grow out.

A healthy balanced diet usually provides all the mineral and vitamins they need, without the need for supplements, but how we look after them can affect our nails’ appearance.

However, changes in their colour, shape or surface should be checked with your GP as they can be linked to a wide range of serious medical conditions and medication.

Nail trauma

Nails are made of keratin, a fibrous protein which can dry out, become brittle, soften or tear if we often have our hands in water, detergents or chemicals. Try cotton lining gloves when wearing rubber gloves and moisturising hands/nails daily, or ‘nail strengtheners’, from your pharmacy.

Trauma to the growth plate (matrix) under the cuticle can produce white nail spots, while picking at the cuticle can produce a central groove or allow infection to enter – you’ll notice pain, redness and pus, and may need antibiotics.

This can also happen if trimming nails into a curve leads to an ingrowing toenail. A painful blood clot under a trapped nail can be drained; you may need X-rays to rule out a finger fracture.

Colour changes

Paleness is a sign of anaemia, but white nails may be congenital or signal liver/kidney disease. A green nail may contain pseudomonas bacteria, and yellow or brown nails may indicate jaundice, lung disease, thyroid problems, fungal infections – or regular nail polish use.

Dark streaks often develop in people with darker skin, and in fungal infections, but they can occasionally be caused by tiny haemorrhages.

Rarely, the skin cancer malignant melanoma can develop as a persistent, usually dark, spot or streak.

Shape changes

Spoon-shaped inward curving can be caused by iron deficiency anaemia or haemochromatosis (too much iron), as well as Raynaud’s disease (blue/white fingers when it’s cold) and immune-system disorders.

You may notice horizontal grooves across several nails (Beau’s lines) some weeks after an illness or chemotherapy.

They grow out naturally, but white lines may mean malnutrition. Longitudinal ridging may develop as we get older, but also occurs in alopecia areata (patchy hair loss), rheumatoid arthritis, lichen planus (a skin condition) and circulation problems.

Clubbing (outward curving, with rounding of the fingertips) may be linked to chronic lung, heart, liver and bowel diseases, including cancer.

Splitting and crumbling

If you have psoriasis (a skin disorder) you may notice multiple tiny pits and, like fungal infections, psoriasis can make nails thicker, crumbly and discoloured – this can be treated with steroid or vitamin D creams.

Nails may lift (onycholysis) or become hard, curved and difficult to cut (onychogryphosis). Fungal infections can get in more easily if your nails are already damaged or you have ‘housewife’s hands’ or sweaty feet. Loose nails can be due to trauma, over-manicuring or a range of medical problems – cut them back to where they’re still attached.

4 ways to help fungal nail infection

1. Get the diagnosis confirmed – analysing nail clippings can reveal whether it’s caused by candida (thrush), another type of fungus or a medical condition.
2. If only one or two nails are affected, try amorolfine lacquer or tioconazole paint from the pharmacy. Treatment takes six to 12 months.
3. Your GP may prescribe antifungal tablets, such as terbinafine, for several months.
4. Help prevent recurrence by keeping nails clean and dry, wearing natural fibres (socks and shoes) to reduce sweating, not sharing towels or nail clippers, and wearing flip-flops around swimming pools and changing rooms.