Double Trouble: An Uncommon Case of Ocular Toxoplasmosis in a Systemic Lupus Erythematosus (SLE) Patient

Systemic lupus erythematosus (SLE) is a chronic autoimmune condition characterized by immune dysregulation and use of immunosuppressive therapy, predisposing patients to opportunistic infections. Although infections are a major cause of morbidity and mortality in SLE, ocular toxoplasmosis is rarely reported in these patients and may pose a diagnostic challenge due to its ability to mimic other inflammatory or infectious ocular conditions. Early recognition is essential for timely management and improved visual outcomes. Here we report the case of a 21-year-old woman, a known case of SLE on maintenance immunomodulatory therapy, who presented with a blurring of vision in the right eye since 15 days. Ocular examination revealed vitritis with an active focus of necrotizing retinochoroiditis. Multimodal imaging, including ultrawide field fundus photography, fundus autofluorescence, and spectral domain optical coherence tomography, supported the clinical diagnosis of ocular toxoplasmosis. Serological evaluation showed positive immunoglobulin G (IgG) for Toxoplasma gondii, with negative IgM. The patient was treated with oral trimethoprim-sulfamethoxazole and corticosteroids, resulting in a progressive clinical improvement and resolution of the lesion with scarring. During follow-up, the patient also developed an SLE flare and herpes zoster infection, highlighting the complexity of persistent immune dysregulation in such patients, despite apparent clinical stability. Although uncommon, ocular toxoplasmosis should be considered in the differential diagnosis of posterior uveitis in SLE patients. Clinical examination supported by multimodal imaging remains crucial for diagnosis, particularly when serological tests are inconclusive. Prompt diagnosis and appropriate therapy can lead to favourable visual outcomes and prevent potentially life-threatening systemic complications.