Irritant diaper dermatitis (IDD) is frequently observed in young children but can affect individuals throughout their lifespan. The broader term incontinence-associated dermatitis (IAD) is used to describe inflammatory skin reactions from prolonged exposure to urine and/or feces. This review compares IAD and IDD in pediatric and geriatric populations, focusing on their pathogenesis, clinical considerations, and management. Both conditions involve prolonged bodily fluid exposure disrupting the skin barrier, making infants and older adults particularly susceptible due to their age-related skin characteristics. Factors such as fecal enzyme activity and diet in infants, and medications and comorbidities in older adults, also influence presentation. Particularly for IAD in the geriatric population, accurate diagnosis and differentiation from other conditions like pressure injuries and intertriginous dermatitis is crucial. Management prioritizes prevention, which includes frequent absorbent product changes and barrier creams. If the condition develops, treatment varies with severity, from barrier applications for mild cases to topical steroids for severe cases. Antifungals or antibiotics may be required for cases with superimposed infections. Future initiatives should concentrate on overcoming the difficulties related to IAD and IDD, such as alleviating physical discomfort, mitigating economic impact, and developing standardized terminology and research specifically tailored to geriatric care.