Nail Bed Sporotrichosis in a Patient with Psoriasis Arthritis Treated with a TNF Blocker: A Case Report

Introduction: Sporotrichosis is a granulomatous infection caused by Sporothrix species, typically following traumatic inoculation. Brazil is an endemic area, and zoonotic transmission from cats has become the predominant route of infection. Nail bed involvement is extremely uncommon, likely due to the protective barrier of the nail plate. Case Presentation: We report a 51-year-old female, who cared for domestic and stray cats, with cutaneous and arthropathic psoriasis under treatment with methotrexate and adalimumab, who developed a painful, ulcerated lesion on the nail bed and folds of the right third finger 5 days after minor trauma. The lesion was friable, erythematous, and yellowish, associated with onycholysis and nodular lymphangitic spread on the ipsilateral forearm. Histopathology and fungal culture confirmed Sporothrix schenckii. Immunosuppressive therapy was suspended, and oral itraconazole 200 mg twice daily was administered, leading to complete clinical resolution. Conclusion: This case illustrates an uncommon presentation of lymphocutaneous sporotrichosis involving the nail unit in an immunosuppressed patient. The patient showed complete resolution of the condition after treatment with itraconazole.