Which diagnostic modality is used to confirm molluscum contagiosum when the clinical presentation is uncertain?

Study for the Medical Council of Canada Qualifying Examination (MCCQE) I. Engage with flashcards and multiple-choice questions with detailed feedback. Prepare confidently!

When a skin lesion’s appearance isn’t conclusive, getting a definitive diagnosis from tissue is the most reliable approach. Molluscum contagiosum is caused by a poxvirus, and its true diagnosis is confirmed by histopathology after obtaining a sample. Curettage provides material from the lesion, and under the microscope you see large eosinophilic intracytoplasmic inclusion bodies within keratinocytes—Molluscum bodies—within an epidermal layer that shows otherwise characteristic changes. This histologic pattern is diagnostic for molluscum contagiosum and the procedure also helps treat by removing the lesion.

Blood antibody testing wouldn’t reflect a localized skin infection and isn’t useful for confirming molluscum. PCR could detect viral DNA but isn’t routinely required for confirming a skin lesion and isn’t as immediately definitive as histology. Observation alone would not yield confirmation and could miss alternative diagnoses.