Toenail fungus infections are caused when fungi start an infection in the bed underneath the toenail. Also called onychomycosis, these infections cause nail discoloration, thickened nails, and crumbling edges. Toenails may also have a dullness and distorted shape.
This type of infection is caused by fungi called dermatophytes, which are common causes of athlete’s foot. Athlete’s foot, or tinea pedis, is a type of foot fungus problem that can lead to toenail fungus invasion if left untreated. While these two problems are caused by dermatophytes, it is not uncommon to develop a toenail infection without having any foot fungus symptoms from athlete’s foot.
Toenail infections are classified into one of four categories. Distal subungal onychomycosis is the most common toenail fungus infection. It is caused by the Trichophyton rubrum species of the dermatophytes. This fungus targets the nail bed and underside of the toenail.
White superficial toenail infections are the second classification. These infections occur when fungi infect the layers of the nail and create white spots. It can easily be misdiagnosed, so testing is often done to confirm a fungal infection.
When the fungi infect the new nail growing at the proximal nail fold, the infection is classified as proximal subungal onychomycosis. The proximal nail fold is the section of the skin located just before the cuticle. While these toenail fungus infections are rare, they occur most often in people who have a compromised immune system and cannot effectively fight off a fungal invasion.
Candidal fungus infections are caused by the candida dermatophyte species. This particular fungus is most commonly found to infect the toes of people whose feet stay damp constantly. The toenail fungus infections occur in sections of the toenail that have sustained previous damage.
The fungi that cause toenail infections thrive in moist and warm environments, such as shower stalls and indoor swimming areas. These fungi are generally harmless and do not cause problems unless someone has tiny cuts or spots where the nail and the nail bed are separated. The fungi invaded these spaces and grow rapidly because the foot exposes them to more moisture and warmth while in socks and shoes.
Toenail fungus infections are difficult to completely cure, mainly because of the location. Anti-fungal topical creams are often prescribed. Additionally, a doctor may also prescribe an anti-fungal nail polish. Both treatments are used for about 12 weeks, but full repair of visible damage does not occur until the new infection-free sections of the nail grow out.