Management of Neurosyphilis with Severe Penicillin Allergy

Primary Recommendation: Desensitization

The Centers for Disease Control and Prevention recommends that patients with neurosyphilis and severe penicillin allergy should undergo penicillin desensitization followed by standard penicillin G treatment, as this remains the only proven effective therapy with adequate evidence 1, 2, 3
All guidelines consistently state that patients with neurosyphilis and penicillin allergy should be desensitized to penicillin rather than using alternative antibiotics, with no alternative antibiotics systematically evaluated or proven effective for neurosyphilis treatment 1, 2, 3, 4
After successful desensitization, treatment with aqueous crystalline penicillin G 18-24 million units per day IV for 10-14 days is recommended 2, 5

Ceftriaxone 2 grams daily for 10-14 days may be considered if desensitization is refused or not feasible, but cross-reactivity with penicillin occurs in approximately 10% of penicillin-allergic patients, and this option carries substantial risk 4, 6, 7

Repeat CSF examination every 6 months until cell count normalizes, with CSF white blood cell count being the most sensitive measure of treatment effectiveness 2, 5, 6, 7
Quantitative nontreponemal serologic tests should be repeated at 6, 12, and 24 months 7

All patients with neurosyphilis must be tested for HIV, with HIV-positive patients requiring closer monitoring due to higher rates of neurologic complications and treatment failure 2, 4, 5, 6, 7
Patients with syphilitic eye disease require ophthalmology consultation and should be treated with neurosyphilis regimens 6, 7