A 43-year-old man with HIV is seen in clinic with a 2-week history of headache and blurry vision in his left eye. He is urgently referred to an ophthalmology clinic, where a dilated funduscopic examination reveals anterior uveitis in his left eye. Laboratory testing shows a positive syphilis enzyme immunoassay (EIA). A brain computed tomography (CT) is performed and is normal. Subsequently, a lumbar puncture was performed that showed no abnormal findings on analysis of the cerebrospinal fluid. A serum rapid plasma reagin (RPR) result returns positive with a titer of 1:512. He reports swelling of his throat and difficulty breathing after an hour after receiving oral penicillin.