The harmful effects of excessive moisture on a patient’s skin are well known. While traditionally considered an issue only encountered in continence care and older people, it is now recognised that the harmful effects of excessive moisture can occur across the lifespan and in various patient groups. The term ‘moisture-associated skin damage’ describes the spectrum of inflammatory damage that occurs in response to the prolonged exposure of a patient’s skin to perspiration, urine, faeces or wound exudate. It is generally accepted that moisture-associated skin damage consists of four conditions: incontinence-associated dermatitis, intertrigo, peristomal moisture-associated dermatitis, and periwound moisture-associated dermatitis. This article describes the aetiologies of each of the different types of moisture-associated skin damage, and outlines the nursing interventions required for their prevention and management.