You may have nail fungus if one or more of your nails are:
Whitish to yellow-brown discoloration
Brittle, crumbly or ragged
Distorted in shape
A dark color, caused by debris building up under your nail
Smellling slightly foul
Nail fungus can affect fingernails, but it's more common in toenails.
Fungal nail infections are caused by various fungal organisms (fungi). The most common cause is a type of fungus called
dermatophyte. Yeast and molds also can cause nail infections. Fungal nail infection can develop in people at any age, but it's more common in older adults. As the nail ages, it can become brittle and dry. The resulting cracks in the nails allow fungi to enter. Other factors — such as reduced blood circulation to the feet and a weakened immune system — also may play a role. Toenail fungal infection can start from athlete's foot (foot fungus), and it can spread from one nail to another. But it is uncommon to get an infection from someone else.
Factors that can increase your risk of developing nail fungus include: Being older, reduced blood flow, more years of exposure to fungi and slower growing nails. Sweating heavily, having a history of athlete's foot, walking barefoot in damp communal areas, such as swimming pools, gyms and shower rooms, having a minor skin or nail injury or a skin condition, such as psoriasis, having diabetes, circulation problems or a weakened immune system.
The following habits can help prevent nail fungus or reinfections and athlete's foot, which can lead to nail fungus:
Wash your hands and feet regularly. Wash your hands after touching an infected nail. Moisturize your nails after washing.
Trim nails straight across, smooth the edges with a file and file down thickened areas. Disinfect your nail clippers after each use.
Wear sweat-absorbing socks or change your socks throughout the day.
Choose shoes made of materials that breathe.
Discard old shoes or treat them with disinfectants or antifungal powders.
Wear footwear in pool areas and locker rooms.
Choose a nail salon that uses sterilized manicure tools for each customer.
Give up nail polish and artificial nails.