Unusual Infectious and Autoimmune Dermatopathology Cases: Cryptococcosis, Leptospirosis, and Mpox-Associated Pemphigus Vulgaris

Conclusions

• The presentation argues that unusual skin eruptions can reveal rare systemic or opportunistic infections, so dermatopathology remains crucial for diagnosis.
• Primary cutaneous cryptococcosis can present as a localized ulcerative lesion in an apparently immunocompetent patient and may require treatment as disseminated disease because of the risk of severe outcomes.
• Environmental exposure histories matter, because the cryptococcosis case suggests a contaminated or unsafe topical product, even if the exact source could not be proven.
• Leptospirosis should be strongly considered after freshwater or flood exposure, especially when patients develop fever, jaundice, renal failure, purpura, or conjunctival suffusion.
• Because leptospirosis is often underrecognized outside endemic regions, clinicians need a high index of suspicion and early treatment to reduce mortality.
• Mpox may be temporally associated with new-onset pemphigus vulgaris in rare cases, but the presentation emphasizes that causation cannot be established from a single case.
• Severe blistering disease after mpox can worsen rapidly and may require escalation to systemic immunosuppression and burn-center-level supportive care.
• Overall, the cases highlight that careful history taking, biopsy, special stains, and targeted infectious workup are essential for identifying unexpected causes of complex skin disease.