There are many causes of abnormal nails. The most important cause of progressive, multiple nail disease is a fungal infection. These infections sometimes spread from other areas on the skin previously affected by fungus e.g. simple athletes foot. Some patients have nail infections without any past athletes foot. The finger nails and/or the toe nails may be involved.

The affected nails are usually darker than normal, thicker than normal, more crumbly and roughened on the surface. Nail clippings can be sent for testing to identify the fungus and indicate which treatment is needed.

Usually anti-fungal therapy in the form of tablets or sometimes nail lacquer applications are needed. However, there are other skin diseases which, as well as causing a rash, can also cause changes in the nails. The commonest of these is psoriasis which can affect the nails and sometimes the joints of the fingers and toes.

The nail changes in psoriasis are very similar to the changes in fungal nail disease and tests are usually needed to clarify the situation. Handeczema can also lead to nail changes especially if wet-work (e.g. in hairdressers, bar workers, housewives) is a feature of the disease. This most typically occurs when the skin of the finger tips and nail fold areas is affected by the eczema.