Penicillin remains the first-line treatment
Once the presence of T pallidum is confirmed, treatment depends on the stage of infection (TABLE). In nonallergic patients, benzathine penicillin G is the standard of care. It should be administered as a single intramuscular (IM) dose of 2.4 million units during primary, secondary, and early latent syphilis12 (strength of recommendation [SOR]: C). Late latent and tertiary syphilis require 3 to 4 weeks of penicillin therapy that is usually achieved with 3 weekly IM injections of 2.4 million units benzathine penicillin G12 (SOR: C). Owing largely to the selective permeability of the blood-brain barrier, neurosyphilis requires a larger dose of 3 million to 4 million units intravenous aqueous crystalline benzathine penicillin every 4 hours for 10 to 14 days12 (SOR: C).
Penicillin desensitization should be considered in penicillin-allergic patients, particularly in those who are pregnant or have HIV infection.12
Treatment success can be determined by a 4-fold decline in RPR/VDRL titer over a period of 3 to 6 months after treatment. During the first 24 hours after initial treatment, patients may develop an acute febrile illness known as the Jarisch-Herxheimer reaction. This is largely the result of massive lysis of the pathogen, spilling large quantities of inflammatory cytokines into the bloodstream.13
Table
Syphilis treatment by stage of infection12
| Stage | Time since exposure | Treatment |
|---|---|---|
| Primary | 10-90 days | Adults Children |
| Secondary | 4-10 weeks | Adults Children |
| Early latent | After primary or secondary stages, <1 year | Adults Children |
| Late latent | >1 year of no symptoms | Adults Children |
| Tertiary | Months to years | Adults See above |
| Neurosyphilis (at any stage) | Any time after infection | Aqueous crystalline penicillin G 18-24 million units/d, administered as 3-4 million units IV every 4 hours or continuous infusion, for 10-14 days Alternative |
| IM, intramuscular; IV, intravenous. | ||
Our patient’s symptoms resolved with penicillin
Given the nebulous history of exposure, we treated the patient as having late latent syphilis (rather than secondary syphilis) and administered 2.4 million units benzathine penicillin G IM weekly for 3 weeks. After this treatment course, the pruritic lesions resolved and the patient’s RPR titer dropped to 1:8 in 3 months.
Our case demonstrates a unique atypical presentation of secondary syphilis. To our knowledge, there is no mention of secondary syphilis mimicking urticaria in the literature. The pruritus that accompanied the lesions was also atypical; however, one study noted 42% of patients experience this symptom in secondary syphilis.14 Fortunately, serological studies confirmed the diagnosis and the patient’s symptoms resolved with standard therapy.
CORRESPONDENCE
Peter L. Mattei, MD, 641 Bainbridge Drive, Mullica Hill, NJ 08062; peterlmattei@gmail.com