What is the first-line treatment for a primary varicella infection in immunocompetent patients?

The first-line treatment for a primary varicella infection, commonly known as chickenpox, in immunocompetent patients is acyclovir. Acyclovir is an antiviral medication that is specifically effective against the varicella-zoster virus (VZV), the causative agent of chickenpox. It works by inhibiting viral DNA synthesis, thereby reducing the duration and severity of the illness.

In typical cases of chickenpox, most immunocompetent patients manage the infection without the need for antiviral therapy, as the disease is usually self-limiting. However, acyclovir is indicated in specific scenarios, such as in patients who are at risk for complications or in cases of severe disease. Starting acyclovir early in the course of the infection can lead to faster recovery and decrease the likelihood of complications, such as bacterial superinfection of the skin lesions.

The other options listed are not suitable for the treatment of varicella in immunocompetent patients. Oseltamivir and rimantadine are antiviral agents used for influenza, while valacyclovir, although effective against herpes viruses, is typically used for conditions like herpes simplex virus infections rather than for typical cases of chickenpox. Thus, acyclovir remains the primary and