Unilateral Focal Retinitis as an Initial Manifestation of Cat-Scratch Disease

We report on a case of focal retinitis as the initial manifestation of cat-scratch disease. A 56-year-old Hispanic woman presented for a routine follow-up examination. A fundus examination of the right eye revealed a white retinal lesion along the inferotemporal artery; this lesion was noted to have progressed after one week of observation. On further inquiry, the patient reported she had seven cats at home, some of which were less than six months old and had recently scratched her. She received empirical treatment for focal retinitis with azithromycin (500 mg daily) and valacyclovir (1 g three times daily), which would cover the most common parasitic, viral, and bacterial etiologies. She was lost to a follow-up examination. However, she continued the same dose of antibiotic and antiviral treatment. Upon her eventual follow-up, three months later, it was noted that the lesion had resolved. The initial work-up revealed that she was positive for Bartonella henselae IgM (1:20) and IgG (1:512), as well as for B. quintana IgG (1:256); however, she was negative for B. quintana IgM. At a four-month follow-up appointment, the B. henselae IgM was negative, the IgG had decreased from 1:512 to 1:64, and the B. quintana antibody test was negative for IgM and IgG, all of which are consistent with an adequately treated case of cat-scratch disease. Focal retinitis can be a rare initial manifestation of cat-scratch disease, which should be considered part of the differential diagnosis in cases of focal retinitis, especially in patients with a history of close contact with young cats. Additionally, oral azithromycin may be considered as a treatment for some cases of cat-scratch-associated focal retinitis.