Nail fungus is a common condition that begins as a white or yellow spot under the tip of your fingernail or toenail. As the fungal infection goes deeper, nail fungus may cause your nail to discolour, thicken and crumble at the edge. It can affect several nails. If your condition is mild and not bothering you it is best to monitor it. If your nail fungus is painful, has caused thickened nails or is uncomfortable then it’s best to have it checked out by your local podiatrist