Adult diaper rash can often be treated at home. We'll explain how to treat and prevent this skin condition. Napkin dermatitis. Diaper rash. Napkin dermatitis can also affect older children and adults that are Other causes of napkin rashes include: Candida albicans;. What Are the Symptoms of a Yeast Diaper Rash? Pin Flip Email Search the site GO. called Candida are most common in babies between 4 and 15 months old.