Illustration copyright 2004 by Nucleus Communications, Inc. All rights reserved. http://www.nucleusinc.com

Athlete's foot is a fungal infection of the skin. A vesicular (blister) infection usually begins with a sudden outbreak of large fluid-filled areas under the skin. The blisters most often develop on the skin of the instep but may also develop between the toes, on the heel, or on the sole or top of the foot.