Disseminated Human Sporotrichosis: A Difficult-to-Manage Case in an Immunocompetent Patient

Sporotrichosis is a subcutaneous mycosis caused by species of the genus Sporothrix , in which infection may occur through traumatic inoculation of the fungus into the skin or mucous membranes. The disease is frequently associated with cat scratches, which are considered the main vectors in urban environments. In this context, this report aims to describe a case of disseminated cutaneous sporotrichosis in an immunocompetent patient with difficult therapeutic management. A 28-year-old female patient from São Luís, Maranhão, presented with disseminated cutaneous sporotrichosis following a cat scratch to the right forearm in October 2024. She reported living with ten cats that had free access to the street. She experienced fever after the trauma, without immediate cutaneous manifestations. In December, an ulcerated lesion appeared at the site of the scratch, followed by the emergence of new lesions on the chest, abdomen, back, upper and lower limbs, and face—predominantly in the nasal region. The lesions were painless and non-pruritic. She sought medical care and underwent fungal culture in January 2025, which isolated Sporothrix from the S. schenckii complex. She also reported headache, nausea, and asthenia. The offending cat had a cervical lesion at the time and was found dead in February. Household contacts did not present similar symptoms. The patient had dyslipidemia treated with simvastatin, negative HIV serology, denied corticosteroid use, consumed alcohol, and was a non-smoker. A new biopsy performed in February 2025 again confirmed Sporothrix from the S. schenckii complex on culture, and histopathology showed diffuse granulomatous dermatitis with granulomas and giant cells. Treatment with itraconazole 400 mg/day was initiated on February 3. Terbinafine 250 mg/day was later added after partial improvement following 30 days of itraconazole therapy, without satisfactory clinical response. On May 27, liposomal amphotericin B was initiated for 10 days, leading to progressive lesion reduction; however, severe hypokalemia and progressive creatinine elevation occurred, making continuation impossible. Itraconazole 400 mg/day was maintained. At outpatient follow-up on June 12, the patient showed clinical improvement while continuing antifungal therapy. This case reinforces the importance of early identification of sporotrichosis, even in immunocompetent patients, as previous reports have identified primary immunodeficiencies that may interfere with favorable disease evolution despite adequate diagnosis and treatment.