Disseminated Pityriasis Versicolor Associated With Type 2 Diabetes Mellitus: A Clinical Case With Immunometabolic Insights.

Pityriasis versicolor (PV) is a common superficial fungal infection caused by Malassezia species, typically confined to seborrheic areas. Disseminated forms are uncommon and may reflect underlying host or environmental factors. We describe a 40-year-old male construction worker from a tropical region presenting with widespread hypopigmented macules and acanthosis nigricans. Direct microscopy confirmed Malassezia infection, and laboratory evaluation revealed previously unrecognized type 2 diabetes mellitus (T2DM) (acylated hemoglobin (HbA1c) 8%, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) 5.2; insulin resistance threshold > 2.5). Baseline liver function tests were normal. The patient achieved complete resolution after two weeks of oral itraconazole (100 mg twice daily) with concurrent initiation of metformin and dietary management. This single, hypothesis-generating case suggests that metabolic dysregulation may serve as a contextual rather than causal factor in PV dissemination, acting together with environmental conditions such as heat and humidity that favor fungal proliferation. We propose a speculative "partial-containment" model in which Malassezia overgrows within lipid-rich, low-inflammation environments, producing azelaic acid that suppresses melanogenesis and results in hypopigmentation. While causality cannot be determined from a single case, multidisciplinary care and metabolic screening may benefit patients with atypical or extensive PV, and prospective studies are warranted to validate these mechanisms.