Urinary wetness increases skin friction, raises the skin pH, makes the skin less cohesive, and makes it more permeable. These effects combine to intensify the action of stool enzymes or other irritants that then inflame the skin. When the outermost layer of skin has been damaged, it is easy for microorganisms such as yeast or bacteria to invade the inflamed skin. In addition to enhancing the activity of other irritants, urine acts as a direct irritant. When the skin is moist it is also more conducive to bacterial growth.
Yeast is by far the most common type of organism found in a perineal rash.
Yeast involvement should be suspected in any perineal rash that has not improved dramatically with 72 hours of appropriate therapy. Current or recent antibiotic use makes a yeast infection even more likely, since this reduces the amount of the skin's 'good' bacteria that fight infection. Take Action Healthy skin is clean, dry skin. As long as there is a need for a protective undergarment, maintaining clean, dry skin is a challenge. Check skin every day for signs of rash or skin breakdown.