From the Guidelines
A syphilis rash is a key symptom of secondary syphilis, typically appearing 3-6 weeks after the initial chancre of primary syphilis heals, and requires immediate medical attention for proper diagnosis and treatment. The rash is usually non-itchy, reddish-brown, and can appear anywhere on the body but commonly affects the palms of hands and soles of feet—a distinguishing characteristic from many other rashes.
Key Characteristics of Syphilis Rash
- Non-itchy
- Reddish-brown
- Can appear anywhere on the body
- Commonly affects the palms of hands and soles of feet If you suspect a syphilis rash, seek immediate medical attention for proper diagnosis through blood tests and physical examination, as recommended by the Centers for Disease Control and Prevention 1.
Treatment Options
- The standard treatment is penicillin G benzathine, administered as a single intramuscular injection of 2.4 million units for early syphilis (primary, secondary, or early latent) 1.
- For late latent syphilis or syphilis of unknown duration, three weekly injections are typically required 1.
- Those allergic to penicillin may receive alternative antibiotics like doxycycline (100mg twice daily for 14 days) or tetracycline. The rash usually resolves within weeks of treatment, but complete follow-up testing is essential to confirm cure, as syphilis is caused by the bacterium Treponema pallidum and is highly contagious through direct contact with syphilitic sores during sexual activity, making it crucial to abstain from sexual contact until treatment is complete and to notify all recent sexual partners so they can be tested and treated if necessary 1.
From the Research
Syphilis Rash
- A syphilis rash is a symptom of secondary syphilis, which can appear as macular, maculopapular, papular, or pustular lesions 2.
- The duration of the rash and the appearance of the secondary lesions are directly correlated, with patients who present early in the course of illness tend to have macular and maculopapular lesions, whereas those who appear later are more likely to have papular or pustular lesions 2.
- The serologic response to treatment is also correlated with the duration of the rash and the appearance of the secondary lesions, with patients whose rash is of short duration and those with macular and maculopapular lesions becoming seronegative sooner than those patients whose rash is of longer duration and who have papular or pustular lesions 2.
Treatment of Syphilis Rash
- The recommended treatment for secondary syphilis is intramuscular benzathine penicillin G, 2.4 million units weekly for two consecutive weeks 2.
- Alternative treatments include doxycycline, which is the preferred recommended second-line agent for the treatment of syphilis 3, 4, and ceftriaxone, which has been shown to be noninferior to benzathine penicillin G in nonpregnant, immunocompetent patients with early syphilis 5.
- Azithromycin is not recommended for routine use due to reported increases in the prevalence of a mutation associated with azithromycin resistance 6.
Serological Response to Treatment
- The serological response to treatment can be evaluated by measuring the rapid plasma reagin (RPR) titer, with a ≥4-fold decline in titer indicating a successful response 3, 5, 4.
- The median time to successful serological response can vary depending on the treatment used, with doxycycline and benzathine penicillin G showing similar response times 3, 4.