Fungal infections in diabetes mellitus

Diabetes mellitus is recognised as a global health problem and has increasingly been associated with fungal infections, as an independent risk factor. Diabetic patients are predisposed to both superficial as well as invasive fungal disease, and account for substantial morbidity and mortality. Recent pandemic of COVID-19 underlined the global problem of mucormycosis, however, the burden of fungal infections among diabetics has a much broader horizon. This review aims to summarise the spectrum of fungal infections encountered among diabetic patients, along with elucidating immunopathogenesis and clinical challenges encountered in diagnosis and management of such infections.

We conducted a narrative review of all published literature focusing on spectrum of fungal infections, immunopathogenesis and clinical challenges encountered in diagnosis and management, among diabetic patients.

Diabetes mellitus facilitates the acquisition and progression of fungal infections via multiple coordinated mechanisms viz. hyperglycemia, impaired immune (innate and adaptive) response, altered microenvironment and endothelial dysfunction. These changes in the milieu contribute to pervasive clinical presentations, ranging from cutaneous and oral candidiasis to invasive fungal diseases like mucormycosis, aspergillosis and cryptococcosis. Besides predisposing to fungal infections, diabetes also serves as a prognostic factor and has been noted to worsen the outcome. Furthermore, the altered microenvironment affects the pharmacokinetics of antifungal drugs and can also reduce the efficacy of antifungal regime, further convoluting and worsening the progression of disease.

Early diagnosis and management of fungal infections is necessary to mitigate the associated morbidity and mortality among diabetic patients. A multidisciplinary approach is imperative as diabetes hampers the effectiveness of conventional antifungal regimens and facilitates antifungal resistance. Regular monitoring of glycaemic index and compliance for drugs, along with lifestyle modifications desired for optimal levels, is pre-requisite for antifungal therapy to exhibit desired action.