Deep Fungal Infection of the Skin with Two Rare Fungi in a Dog Being Treated with Immunosuppressant Therapy: A Case Report

Abstract

Simple Summary An 8-year-old female intact Elo, diagnosed with immune-mediated brain inflammation, is put on immunosuppressive drugs long-term. After 48 weeks of therapy, the dog developed skin lesions on the tail and nasal cavity. This case report presents a serious mixed deep fungal skin infection with two different rare fungi on the same dog, the first report to do so in veterinary medicine. Diagnosing these infections was challenging and required tissue sampling, microscopic examination, and advanced laboratory testing to identify the fungi. Treatment involved a combination of oral antifungal medication as well as ointments, while carefully reducing immunosuppressing drugs to help the body fight the infection without worsening the original disease. Nevertheless, the dog had to be euthanised due to the worsening of the underlying disease. This case report highlights the importance of regular dermatological and clinical checks, early testing of suspicious lesions, and tailored treatment plans for pets on immunosuppressive therapy. Better monitoring of skin lesions and health status could lead to earlier diagnosis and better outcomes, which would benefit animal health and guide veterinarians and animal owners for future action. Abstract Deep fungal skin infections in dogs being treated with immunosuppressant therapy pose a clinical challenge, balancing effective antifungal therapy with a sufficient immune function to control the infection whilst maintaining good control over the original disease. This case report describes the clinical presentation, diagnosis, and outcome of a dog with a concurrent deep fungal infection of the skin with two rare fungi, Purpureocillium sodanum and Alternaria rosae, and this is the first time this agents has been described in veterinary medicine. Challenges included fungal infections at multiple sites and drug–drug interactions between necessary immunosuppressive therapy and antifungals. Persistent lesions and limited therapeutic success emphasise the need for clinicians’ awareness, early diagnosis, individualised case management, and advances in immunosuppressive protocols.