Introduction

Fungi usually make their homes in moist areas of the body where skin surfaces meet: between the toes, in the genital area, and under the breasts. Many fungi that infect the skin (dermatophytes) live only in the topmost layer of the epidermis (stratum corneum) and do not penetrate deeper. Obese people are more likely to get these infections because they have excessive skinfolds. People with diabetes tend to be more susceptible to fungal infections as well.

Strangely, fungal infections on one part of the body can cause rashes on other parts of the body that are not infected. For example, a fungal infection on the foot may cause an itchy, bumpy rash on the fingers. These eruptions (dermatophytids, or id reactions) are allergic reactions to the fungus. They do not result from touching the infected area.

A doctor may suspect a fungal infection upon seeing a red, irritated, or scaly rash in one of the commonly affected areas. The doctor can usually confirm the diagnosis by scraping off a small amount of skin and having it examined under a microscope or placed in a culture medium that will grow the specific fungus so that it can be identified (see Section 18, Chapter 202).