Background/Objectives: Mycoplasma pneumoniae (MP) is a frequent cause of community-acquired pneumonia, but it is increasingly recognized for extrapulmonary complications, specifically Mycoplasma pneumoniae-induced rash and mucositis (MIRM). This systematic review aims to comprehensively assess the frequency of clinical features, diagnostic criteria and outcomes of oral mucositis in patients with confirmed MP infection. Methods: A systematic review was conducted following PRISMA guidelines across PubMed, Web of Science and Scopus, covering the period 2015–2025. Inclusion criteria encompassed in vivo studies, case reports, and case series in English focusing on MP-associated mucositis. Methodological quality was assessed using JBI checklists for case-based evidence and the Newcastle–Ottawa Scale for cohort studies. Two clinical cases were reported. Results: Out of 242 identified records, 42 studies were included, involving 140 patients with a notable male predominance (62%). Oral involvement was reported in 92.9% of cases, often characterized by severe ulcerations, hemorrhagic crusting, and debilitating pain. Intensive Care Unit admission was required in 21.5% of cases due to severe systemic or mucosal disease, with 14.3% necessitating parenteral nutrition. Quality assessment indicated moderate-to-high methodological rigor across most included studies. Conclusions: MIRM represents a significant clinical entity where oral mucositis is a dominant feature, often preceding or overshadowing respiratory symptoms. Early recognition by oral health professionals is crucial to avoid misdiagnosis, ensure appropriate multidisciplinary care, and implement supportive or immunomodulatory therapies that reduce morbidity and hospitalization length.
D’Agostino et al. (2026) studied this question.