Nail problems may be due to a wide range of different causes, including:
- Trauma, whether due to an acute injury (e.g. dropping something on your toe), chronic injury (e.g. toes repeatedly butting up against running shoes), or the nails and surrounding tissues being too closely cropped during a manicure or pedicure.
- Paronychia, an infection of the tissue around the nail, which is often caused by the bacterium Staphylococcus aureus. Paronychia is more likely to occur when the skin around the nail is damaged (for example by nail biting or exposure to irritating chemicals), allowing the infecting organism to enter the body.
- Tinea, a contagious fungal infection that is often picked up by using communal showers (such as at the gym or pool). It is most likely to develop when the area between the toes is moist, as occurs with excessive perspiration or from not properly drying the area. Tinea and other fungal infections are more likely to affect people who are diabetic, spend long periods of time with the hands immersed in water, bite their nails, or use nail polish and artificial nails.
- In-grown toenails occur when part of the nail grows into the skin. They may be due to the nails being trimmed too closely, or wearing shoes that constrict the toes. If not treated quickly, infection may develop. In-grown toenails are most likely to affect people with diabetes, as their peripheral circulation and nerve function may be damaged.
- Skin problems such as eczema and psoriasis.
- The use of certain medicines (e.g. some antibiotics, chemotherapy drugs and malaria drugs).
- Certain chronic health problems, such as rheumatoid arthritis, heart disease and lung disease.
- Cigarette smoking (which can cause discolouration).
- Hands often being wet for extended periods of time (e.g. washing dishes), especially if detergent or soap is present at the same time.
- Nutritional deficiency may lead to nails becoming weak, brittle and poorly formed. For example, a pale-coloured nail bed may indicate iron deficiency, and so may nails that are spoon-shaped (curled up at the edges) or flat. Many natural therapists also believe that a wide range of other nutritional deficiencies may be detrimental to nail health.
In addition, as we get older, the texture of our nails tends to change, and they are more likely to become ridged, brittle or discoloured. They also become thicker, and the growth rate tends to decline .