Can herpes simplex progress as a single lesion or multiple lesions?

Herpes Simplex Virus Lesion Presentation

Herpes simplex virus (HSV) infections can present as either a single lesion or multiple lesions, with multiple lesions being the more common presentation in both primary and recurrent infections. 1

Primary HSV Infection

Primary HSV infection typically presents with more extensive clinical manifestations compared to recurrent episodes:

• Primary infection often manifests as multiple vesicular lesions that may coalesce, particularly in orolabial or genital areas 1
• The infection usually begins with a patch of redness at the site, followed by a localized papular then vesicular rash 1
• These vesicles contain clear fluid with thousands of infectious viral particles that eventually burst, forming shallow ulcers or erosions 1
• In immunocompetent hosts, these episodes typically last less than 10 days but may be prolonged due to secondary bacterial infection 1

Recurrent HSV Infection

Recurrent HSV infections can present with varying severity:

• Recurrences are characterized by the reactivation of latent virus from ganglia, with the localization of primary and recurrent lesions usually coinciding 1
• Classically, each recurrence begins with a sensory prodrome (pain, pruritis) in the affected area, followed by the evolution of lesions from papule to vesicle, ulcer, and crust stages 1
• While recurrent infections can present as a single lesion, they more commonly appear as grouped vesicles in the affected dermatome 1
• Orolabial herpes (typically HSV-1) presents with lesions on the lips that progress through stages of papule, vesicle, ulcer, and crust 1
• Genital herpes (typically HSV-2) presents with mucosal or skin lesions similar to orolabial lesions in appearance and evolution 1

Clinical Variations by Patient Population

The presentation can vary significantly based on the patient's immune status:

• In immunocompromised patients, HSV infections may be more severe with extensive, deep, nonhealing ulcerations 1
• These severe manifestations have been reported most often in patients with CD4+ counts <100 cells/μL 1
• Without adequate treatment, immunocompromised patients may develop chronic ulcerations with persistent viral replication complicated by secondary bacterial and fungal superinfections 1
• In profoundly immunocompromised hosts, skin lesions may continue to develop over a longer period (7-14 days) and generally heal more slowly without effective antiviral therapy 1

Diagnostic Considerations

Due to the variable presentation of HSV infections, laboratory confirmation is essential:

• Clinical diagnosis alone has poor sensitivity and specificity, especially in HIV-seropositive patients 1
• Viral culture, HSV DNA PCR, and HSV antigen detection are available methods for diagnosis 1
• Type-specific serologic assays can be used in asymptomatic persons or those with atypical lesions 1
• The virus detected in genital lesions should be typed, as HSV-1 recurs less frequently than HSV-2 in the genital area 1

Common Pitfalls and Caveats

• HSV infections are often misdiagnosed based on clinical appearance alone, as many cases present with atypical features 1
• Most persons with genital herpes have mild and atypical lesions that may not be recognized clinically 1
• In 80-90% of genital herpes cases, the disease progresses subclinically but may become symptomatic at any time 1
• Single lesions may be mistaken for other conditions such as bacterial infections, traumatic lesions, or other viral exanthems 1
• The presence of grouped vesicles on an erythematous base in a dermatomal distribution is highly suggestive of herpes virus infection 1

In summary, while HSV can occasionally present as a single lesion, particularly in recurrent cases, the classic presentation involves multiple grouped vesicles that progress through predictable stages. Laboratory confirmation is recommended for definitive diagnosis due to the variable clinical presentation.