Oral candidiasis is a frequent fungal condition that disproportionately impacts older adults, individuals with weakened immunity, and patients undergoing oncology therapies. Although widespread, recognizing and managing this infection can be difficult because presentation varies widely and antifungal resistance may complicate care. This study sought to identify which clinical manifestations best indicate oral Candida infections, with particular attention to features linked to poor antifungal response. A secondary aim was to explore whether underlying health issues—such as frailty and coexisting medical conditions—affect vulnerability to infection or influence treatment outcomes. A sample of 57 adults aged ≥65 years (mean age 74) was recruited from oncology and hospitalist services in Northern Ontario. Most participants (65%) were receiving active cancer therapy. Each underwent an oral examination for candidiasis-related signs and symptoms, and fungal swabs were collected at baseline and again two weeks later. Species identification and therapeutic responses were documented. Most infections were due to Candida albicans and improved with standard antifungal therapy. In contrast, infections involving Nakaseomyces glabratus or Pichia kudriavzevii were more likely to continue, aligning with known resistance patterns. Clinically, pseudomembranous presentations—white plaques, tongue coating, taste changes—tended to resolve more readily, whereas erythematous findings, including oral redness and angular cheilitis, were often linked to persistent disease. Although 45% of participants met criteria for moderate to severe frailty, frailty did not demonstrate a significant relationship with persistent or resistant infection. The findings highlight the broad clinical variability of oral candidiasis and emphasize the need for rapid, point-of-care molecular diagnostics to distinguish species and guide timely management, particularly for older or medically complex individuals.
