Atypical Presentation of Frosted Branch Angiitis due to Ocular Toxoplasmosis: A Case Report

Purpose: To report a case of Frosted Branch Angiitis (FBA) secondary to ocular toxoplasmosis in a patient with a retinochoroidal scar in the contralateral eye (OD) and a late active retinochoroiditis in the OS and to compare it with previous reports. Case Description: A 25-year-old female experienced sudden vision loss and eye redness in the left eye (OS). During the initial examination, the best-corrected visual acuity was 20/20 in the right eye (OD) and counting fingers in the OS. Ophthalmological examination of the OD showed a 1-disc diameter scar in the lower nasal mid-periphery. At the same time, OS revealed 2+ cellularity in the anterior chamber and retinal vasculitis with perivascular sheathing, indicative of FBA. Initial treatment included antiviral and corticosteroid therapy (oral and topical), with partial improvement. Aqueous humor polymerase chain reaction confirmed toxoplasmosis as the etiology, necessitating a shift to specific anti-Toxoplasma therapy, which led to clinical improvement. Conclusion: This case highlights the importance of considering in the differential diagnosis of FBA, even in patients with retinochoroidal scars in the contralateral eye. Close follow-up is essential after FBA resolution, as new lesions may develop. Prompt anti- therapy and corticosteroid treatment are critical for preserving visual outcomes, as delays in diagnosis and treatment can lead to significant complications.