A fungal nail infection gives a thickened, discoloured, and brittle nail and is caused by a fungus that grows inside the nail. A thickened and brittle nail is sometimes also called onychauxis. In most cases, onychauxis is caused by a fungal infection, but not always. A thickened nail can also be caused by a disturbance in the growth of the nail which is not caused by a fungus but, for example, by badly functioning blood vessels, old age, by a skin disease such as psoriasis, or spontaneously.
Fungal nail infections are very common. It is estimated that 5% of the Dutch population has one or more nails with a fungal infection and is most times found on the toenails (98%). Fungal nail infections on the fingernails are rare. The medical term for a fungal nail infection is onychomycosis.
It is not always necessary to treat a fungal nail infection. When you do not experience any complaints or you do not find it too cosmetically disturbing, you can also choose not to treat the nail(s) because the treatment is not that simple and often involves taking medication for months (anti-fungal tablets). But there can be medical indications for which it is advisable to treat the fungus. This can be, for example, when you have diabetes or a reduced immune system, or when the fungal infection causes other problems such as erysipelas, or eczema with blisters on the hands or feet (vesicular eczema).