Acute rubella retinal pigment epitheliitis in an adult.

A 50-year-old man who had been taking betamethasone for 20 days experienced a slight bilateral decrease in visual acuity. There were localized dark-gray atrophic lesions at the posterior pole, accompanied by a diffuse detachment of the sensory retina. The retinal vessels appeared to be normal and only minimal anterior uveitis was present in the more severely affected eye. Fluorescein angiograms showed no masking of choroidal fluorescence in the early phase and late-phase fluorescein angiograms showed multifocal leakage of the dye into the subretinal space. Electro-oculographic findings were abnormal only during the acute stage in the more severely affected eye and returned to normal within three months. The retinal detachment spontaneously resolved within three months; visual acuity returned to normal but some atrophic areas remained in the retinal pigment epithelium. Because the antibody titer to rubella was 1:1,028 during the acute stage but decreased to 1:257 within one month, we believe this patient had rubella retinitis, a rare condition in adults. The betamethasone may have made him more susceptible to the viral infection.