Abstract Introduction Neurosyphilis occurs in approximately 1-2% of syphilis cases, with ocular involvement being a rare but vision-threatening complication. Penicillin remains the gold standard for treatment; however, penicillin-induced anaphylaxis can occur in roughly 0.004-0.015% of treatment courses. We report a case of neurosyphilis with ocular involvement complicated by a severe anaphylactic reaction to penicillin, posing a significant therapeutic challenge. Description A 34-year-old woman presented to the emergency department with complaints of sharp right-sided eye pain, markedly diminished visual acuity, and ptosis. Examination revealed a dilated, non-reactive, "down-and-out" pupil; anterior chamber flare with cells; and a confluent cornea with keratic pigmentation, limiting fundoscopic visualization. Her medical history was significant for poorly controlled HIV with prior opportunistic infections and recent treatment for syphilis with a single dose of IV penicillin G. A prior lumbar puncture was negative for CSF VDRL, and a repeat attempt was unsuccessful. Despite this, her clinical presentation was highly suggestive of ocular syphilis with syphilitic uveitis and cranial nerve involvement, further supported by a positive treponemal test and an RPR titer of 1:1.Upon administration of IV penicillin, the patient developed acute dyspnea, urticarial rash and facial swelling, consistent with anaphylaxis. An attempt at penicillin desensitization elicited a similar reaction. Prompt treatment with epinephrine stabilized her, avoiding ICU admission. Given the anaphylactic response, she was transitioned to IV ceftriaxone for 14 days, resulting in significant improvement and partial reversal of ocular symptoms at follow-up. Discussion Ocular syphilis is classified as a neurosyphilis equivalent, even when CSF analysis is unremarkable. HIV coinfection increases the risk of neurosyphilis, often leading to atypical or accelerated disease presentations. Cranial nerve involvement is a rare but recognized manifestation. A high index of suspicion—guided by the patient’s medical history—facilitated timely diagnosis and likely prevented more severe complications, including meningitis and seizures. Alternative antibiotic regimens such as ceftriaxone may serve as viable options in cases of penicillin allergy, though close monitoring is essential. This abstract is funded by: None
Rizvee et al. (Fri,) studied this question.