The athlete's foot is caused by a fungal infection of the skin on the foot. The majority of these infections are caused by one of three fungal agents called dermatophytes. The athlete's foot is by far the most common fungal infection of the skin. The infection can be either acute or chronic. The recurrent form of the disease is often associated with fungal-infected toenails. The acute form of the infection most often presents with moisture, scaling between the toes with occasional small blisters and/or fissures. As the blistering breaks, the infection spreads and can involve large areas of the skin on the foot. The burning and itching that accompany the blisters may cause great discomfort. The infection can also occur as isolated circular lesions on the bottom or top of the foot. As the skin breaks down from the fungal infection, a secondary bacterial infection can ensue.