A fungal nail infection begins as a small white or yellow spot under the nail but can spread to discolour the nail, turning it white, yellow, brown green or black. The infected nail can thicken and may become misshapen, losing its flexibility and becoming dry and brittle. The appearance of the nail can be rougher and have ridges.
Nail fungus is highly contagious and can spread to adjacent toenails, the skin around the nail and even to fingernails via any form of direct contact. A fungal toenail infection often occurs as a secondary infection to athlete’s foot, as the fungus spreads from the skin between the toes to the toenail itself.
If left untreated, a fungal nail infection can cause the nail to thicken and distort, eventually drying out and detaching from the nail bed. The thick, distorted nail can become a source of discomfort when walking, and as the toenail begins to separate from the nail bed, it can become painful.