Toenail fungus onychomycosis is caused by a group of fungi known as dermophytes this group thrives on skin and on keratin the main component of hair and nails the fungus gets under the nail. Athletes foot foot fungus posted by feetdocsadmin comments off on athletes foot foot fungus typically contracted in damp communal areas such as public pools locker rooms or showers athletes foot is a highly contagious persistent ailment caused by fungal growth on the feet the most commonly affected area is between the toes athletes foot often first appears as an itchy . Onychomycosis foot fungus onychomycosis is a fungal infection of the toenails or fingernails this ailment causes fingernails or toenails to thicken discolor disfigure and split at first glance onychomycosis appears to be only a cosmetic concern however without treatment the toenails can become abnormally thick forcing the toe to press . Toenail fungus onychomycosis onychomycosis is a term used to describe a typically slow growing fungal infection beneath the toenail symptoms include a white or yellowish discoloration the thickening and flaking of the nail and the separation of the nail from the nail bed