Fungal Nails
Fungal nails are very common and generally affect toenails more than fingernails. Fungal nails particularly affect those over 55 and younger people who share communal showers, e.g. swimmers, athletes etc.
Treatment
To confirm a definite diagnosis a clipping of the nail would need to be taken by your GP to be sent away to a laboratory for testing. However, treatment can still be applied to the nails which could prevent the spreading of the infection and encourage a normal regrowth.