Bilateral Toxoplasmosis Scars but Unilateral Reactivation of Retinitis

It is not unusual to have bilateral toxoplasmosis scars but unilateral reactivation of retinitis as shown in this case. This woman had been followed for years with visual acuity of 20/20 right eye, 20/30 left eye until she came in with new blurred vision of the right eye and visual acuity reduced to 20/63 on the right. Two toxoplasmosis scars are seen in the right eye (white and green arrows) and one in the left eye (yellow arrow), but reactivated retinitis is seen in the right eye only (blue arrow). With clindamycin therapy, 300 mg four times per day, the reactivation was rendered inactive and the visual acuity returned to 20/30 in the right eye. As typical in these cases with reactivated disease, the IgG serology was positive, but the IgM serology was negative.