Can herpangina be treated with acyclovir?

Acyclovir is Not Effective for Herpangina

Acyclovir should not be used to treat herpangina because this condition is caused by enteroviruses (primarily Coxsackievirus A and Enterovirus A), not herpes simplex virus, and acyclovir has no activity against enteroviruses. 1, 2

Understanding the Disease Etiology

Herpangina is fundamentally different from herpes infections despite the similar-sounding name:

• Herpangina is caused by enteroviruses, most commonly Coxsackievirus-A, Enterovirus-A, and Echovirus, with Coxsackievirus A2 and A4 being particularly prevalent 1, 3
• The disease presents with characteristic vesicular lesions on the tonsils and soft palate, fever, and sore throat 4, 1
• Acyclovir is specifically designed to inhibit herpesvirus DNA polymerase and has demonstrated activity only against herpes simplex virus and varicella-zoster virus 2, 5

Why Acyclovir Fails in Herpangina

The mechanism of action makes acyclovir ineffective:

• Acyclovir requires viral thymidine kinase (present in herpesviruses) for activation and specifically targets herpesvirus DNA polymerase 2, 5
• Enteroviruses are RNA viruses without DNA polymerase, making them completely resistant to acyclovir's mechanism of action 1
• Clinical guidelines for acyclovir use exclusively address herpes simplex and varicella-zoster infections, with no mention of enteroviral diseases 6

Appropriate Treatment for Herpangina

The correct management approach is entirely supportive:

• Treatment is mainly symptomatic with adequate hydration, dietary modifications (avoiding salty, spicy, and fried foods), and restriction of physical activity 4, 1
• Topical oral sprays such as benzydamine may provide symptomatic relief 4
• The disease is self-limited, typically lasting 4-6 days with excellent prognosis 1
• Antiviral drugs targeting enteroviruses (not acyclovir) may be considered, though evidence is limited 4

Critical Clinical Pitfall

The most important caveat is avoiding the assumption that all oral vesicular lesions are herpes-related. The name "herpangina" is misleading—it refers to the appearance of the lesions (herpetic-like), not the causative agent. Diagnosis should be based on:

• Characteristic posterior pharyngeal location (tonsils and soft palate) rather than anterior mouth involvement typical of herpes simplex stomatitis 1
• Epidemiological context (common in children, often epidemic) 1, 3
• Virological confirmation via PCR when needed 4, 1