Diagnostic Approach for Suspected HSV Oral Ulcers

Initial Diagnostic Steps

For patients presenting with suspected HSV oral ulcers, nucleic acid amplification tests (NAATs) or PCR from lesion samples should be the first-line diagnostic approach, as they offer the highest sensitivity and specificity for detecting HSV infection, according to the Clinical Infectious Diseases guidelines 1
Collect samples directly from vesicular or ulcerative oral lesions using proper technique for optimal diagnostic yield, as recommended by Eurosurveillance 2, 3
Submit samples for HSV NAAT/PCR testing that can differentiate between HSV-1 and HSV-2, following the guidelines from Clinical Infectious Diseases 1

Use cotton-wool or Dacron swabs to collect material from lesions, as suggested by Eurosurveillance 2
For vesicular lesions, pierce the vesicle and collect fluid, according to Eurosurveillance 3
Transport samples promptly in appropriate viral transport media, as recommended by Eurosurveillance 3

NAAT/PCR testing is the first choice, with the highest sensitivity (11-71% superior to viral culture) and can detect and type HSV in a single reaction, providing results within approximately 2 hours, as stated in Eurosurveillance 3
Viral culture is the second choice, but less sensitive than PCR, with isolation rates varying by lesion stage, and results typically available in 24-72 hours, according to Eurosurveillance 3

Consider type-specific HSV serologic testing if lesions have healed and direct testing is not possible, or if recurrent episodes occur but direct testing has been negative, as recommended by Clinical Infectious Diseases 1
Type-specific serologic assays that differentiate between HSV-1 and HSV-2 should be used, according to Clinical Infectious Diseases 1

For suspected HSV encephalitis, detection of HSV DNA by PCR in CSF is the diagnostic test of choice, as stated in MMWR Recommendations and Reports 6
For immunocompromised patients, more aggressive diagnostic evaluation is warranted, and consider early biopsy and surgical debridement, as recommended by Clinical Infectious Diseases 5

The clinical differentiation of HSV infection from other infectious and non-infectious causes of oral ulceration is difficult, and laboratory confirmation should always be sought, according to Eurosurveillance 2
Typing of HSV is important as it provides prognostic information, with HSV-1 recurs less frequently than HSV-2 in the genital area, as stated in MMWR Recommendations and Reports and Clinical Infectious Diseases 7, 1