Can Syphilis Cause Swollen Testicle?
Yes, syphilis can cause testicular swelling through orchitis or epididymo-orchitis, though this is an uncommon manifestation that typically occurs in late syphilis or in immunocompromised patients, particularly those with HIV coinfection.
Clinical Manifestations of Syphilitic Orchitis
Syphilitic involvement of the reproductive organs is recognized as a rare manifestation of late syphilis, which typically becomes clinically apparent only after 15-30 years of untreated infection 1. However, more acute presentations can occur, particularly in specific patient populations.
Key Clinical Presentations:
Late syphilis manifestations: The reproductive organs can be involved as part of late benign syphilis, though this is rare compared to cardiovascular, skin, and bone involvement 1
HIV-coinfected patients: Syphilitic orchitis and epididymo-orchitis have been documented in HIV-positive immunocompromised patients, where it can present as a scrotal abscess or testicular mass 2
Secondary syphilis: Disseminated early syphilis can cause orchitis as part of a multisystem presentation, including ulceronodular rash and other organ involvement 3
Diagnostic Considerations
Critical Pitfall - Mimicking Testicular Cancer:
Syphilitic testicular lesions can closely mimic testicular malignancy on physical examination and imaging, presenting as painless testicular masses that appear as hypoechoic lesions on ultrasound 4, 3. This is a crucial diagnostic trap that can lead to unnecessary orchiectomy.
Diagnostic Approach:
Serologic testing is mandatory: Both nontreponemal (VDRL, RPR) and treponemal tests (FTA-ABS, MHA-TP) should be performed in any patient with unexplained testicular swelling or mass 5
Tumor markers: Check lactate dehydrogenase, alpha-fetoprotein, and human chorionic gonadotropin to help differentiate from malignancy 4
HIV testing: All patients with syphilis should be tested for HIV, as coinfection increases the likelihood of atypical presentations including orchitis 5, 6
Treatment Approach
For Confirmed Syphilitic Orchitis:
Treatment depends on the stage of syphilis and should follow standard CDC guidelines, with testicular-sparing conservative management being appropriate when malignancy is excluded 4.
Primary/Secondary Syphilis with Orchitis:
- Benzathine penicillin G 2.4 million units IM as a single dose 5, 6
- For penicillin-allergic patients: Doxycycline 100 mg orally twice daily for 14 days 5
Late Latent Syphilis:
- Benzathine penicillin G 7.2 million units total, administered as three doses of 2.4 million units IM at 1-week intervals 5
- For penicillin-allergic patients: Doxycycline 100 mg orally twice daily for 28 days 5
If Neurosyphilis is Suspected:
- Consider CSF examination, especially in HIV-positive patients with high RPR titers or neurological symptoms 6
- If confirmed: Aqueous crystalline penicillin G 18-24 million units IV daily for 10-14 days 5, 6
Special Considerations
HIV-Positive Patients:
- More likely to have atypical presentations including orchitis 6, 2
- May experience more rapid disease progression and florid manifestations 6
- Require closer follow-up with repeat quantitative nontreponemal tests at 3,6,12, and 24 months 6
Conservative Management Success:
Complete resolution of testicular masses has been documented with antibiotic treatment alone, avoiding unnecessary orchiectomy 4. Follow-up ultrasound at regular intervals (e.g., 10 months post-treatment) can confirm resolution 4.
Partner Management:
All sexual partners exposed within 90 days before diagnosis should be treated presumptively, even if seronegative 7, 6.
Clinical Bottom Line
While testicular involvement in syphilis is uncommon, it represents a critical diagnostic consideration that can prevent unnecessary surgical intervention. The key is maintaining a high index of suspicion, particularly in men who have sex with men, HIV-positive patients, and anyone with risk factors for syphilis presenting with testicular swelling or masses 8, 3.