Diagnostic Workup for Penile Bumps in an 18-Year-Old Male
For an 18-year-old male with asymptomatic penile bumps and a history of chlamydia, perform a comprehensive STI screening with urine NAAT testing for chlamydia and gonorrhea, visual inspection to characterize the lesions, and consider testing for syphilis and HIV given his STI history. 1, 2
Initial Assessment and Visual Examination
Carefully inspect the penile lesions to differentiate between infectious causes and benign conditions like folliculitis from shaving:
- Look for specific characteristics: vesicles or ulcers (suggesting herpes), painless ulcers (syphilis), wart-like growths (HPV), or follicular pustules consistent with razor burn 3
- Document location, size, and distribution of the bumps to guide differential diagnosis
- Ask about recent shaving practices and timeline of lesion appearance relative to hair removal 3
STI Screening Protocol
Given his age, sexual activity, and prior chlamydia infection, comprehensive STI testing is warranted regardless of symptom status:
Primary Testing (Mandatory)
- First-catch urine specimen using NAAT for chlamydia and gonorrhea - this is the preferred non-invasive method for males with sensitivity 86-100% and specificity 97-100% 1, 2, 3
- Syphilis serology (treponemal and nontreponemal antibodies) - essential given his STI history and to rule out painless chancre 3, 2
- HIV screening - recommended for all patients diagnosed with any new STD 2, 3
Additional Testing Based on Sexual History
- Assess sexual practices to determine anatomical sites for testing - if he has oral or receptive anal contact, pharyngeal and rectal swabs are necessary 1, 4
- HSV testing if lesions are vesicular or ulcerative - NAAT has high sensitivity for symptomatic HSV 3
Key Clinical Considerations
The CDC emphasizes that urine-based NAAT is preferred over urethral swabs for asymptomatic males due to higher patient acceptability and comparable diagnostic accuracy 1. Traditional non-culture tests on urethral specimens have limited sensitivity in asymptomatic men and are not recommended 1.
Important caveat: False-positive urine results may occur in older men with non-chlamydial urinary tract infections, though this is less relevant for an 18-year-old 1, 5
Reinfection Risk Assessment
This patient requires repeat testing 3-6 months after his previous chlamydia treatment regardless of current symptoms, as men with documented chlamydial infections have high reinfection rates within 6 months 2. His current presentation may represent:
- Reinfection from untreated partners 2
- A new STI acquisition 2
- Non-infectious dermatologic condition (folliculitis from shaving)
Partner Management
All sexual partners within the preceding 60 days should be referred for evaluation and empiric treatment if chlamydia or gonorrhea is detected 2. The high likelihood of partner reinfection necessitates this approach even if partners are asymptomatic 2.
Testing Timing and Follow-Up
- Do not perform test-of-cure at 3-4 weeks unless symptoms persist or therapeutic noncompliance is suspected 2
- Schedule repeat screening at 3 months if any STI is detected, as this is when reinfection rates are highest 2, 6
- Instruct patient to abstain from sexual activity for 7 days after single-dose therapy or until completion of multi-day regimens 2
Common Pitfalls to Avoid
- Do not rely solely on symptom-based screening - 70% of chlamydia and trichomoniasis infections and 53-100% of extragenital gonorrhea/chlamydia are asymptomatic 3
- Do not use urethral swabs for asymptomatic screening when urine NAAT is available - it's less acceptable to patients with no diagnostic advantage 1
- Do not assume "razor burn" without STI testing in a sexually active young male with prior STI history - this population has high prevalence rates requiring screening regardless of clinical appearance 2
- Do not order serum chlamydia serology - it has no value in diagnosing genital tract infections as it cannot distinguish current from past infection 5