The word “intertrigo” comes from the Latin, terere, to rub, a catch-all word for the more descriptive term “intertriginous dermatitis.” Thus, when used in its more inclusive sense, intertrigo refers to an inflammatory condition of skinfolds. Intertriginous areas are places where skin is subject to the friction of repeated movement, chafing, obesity, increased local heat, and maceration from retained moisture and from topical applications, all of which serve to provide an excellent environment for potential irritant, fungal, as well as bacterial complications. Both the axillae and inguinal creases are “hot spots” for intertrigo.

Besides the inguinal creases and axilla, the body has other intertriginous appositional places such as the inframammary areas (see Fig. 11-53), finger webs (see Fig. 14-28), toe webs, perineum, and abdominal creases, all represent two opposing surfaces that are incessantly in intimate contact.

The potassium hydroxide (KOH) test, Gram stain, and bacterial culture are useful to exclude primary or secondary infection and to guide therapy. The sun-shaded axillae and inguinal creases are unlikely to absorb much in the way of ultraviolet exposure and are generally spared many skin cancers, although various benign skin growths such as skin tags and melanocytic nevi are commonly found there.

Since both the inguinal and axillary creases share many of the same cutaneous disorders, they will be discussed together in this chapter.