A 28-year-old woman presents with painful vesicular lesions on the vulva, fever, and dysuria. PCR confirms HSV-2 infection. Which is the most common site of recurrent HSV-2 infection in women?

Explanation

## Most Common Site of Recurrent HSV-2 **Key Point:** HSV-2 establishes latency in the sacral dorsal root ganglia (DRG), making the sacral dermatome (S2–S4) the most common site of recurrent genital herpes in women. ### Anatomical Basis of Latency & Recurrence Herpes simplex viruses (both HSV-1 and HSV-2) establish latency in sensory ganglia that innervate the site of primary infection: - **HSV-2 (genital):** Sacral DRG → sacral dermatome recurrence - **HSV-1 (orofacial):** Trigeminal ganglion → trigeminal dermatome recurrence Viral reactivation follows the same neural pathway, causing recurrent lesions in the same dermatome as the primary infection. ### Why Sacral Dermatome? | Feature | Details | |---------|----------| | **Primary site** | Genital mucosa (vulva, vagina, penis) | | **Innervation** | Sacral nerves (S2–S4) | | **Latency site** | Sacral dorsal root ganglia | | **Recurrence pattern** | Same dermatome (S2–S4) | | **Frequency in women** | ~90% of recurrences occur in sacral distribution | **Clinical Pearl:** Recurrent HSV-2 lesions in women typically appear on the labia majora, labia minora, perineum, and buttocks—all supplied by S2–S4 nerves. Men may have recurrence on the glans, shaft, or perianal area (also S2–S4). **High-Yield:** The dermatome of recurrence mirrors the dermatome of primary infection. This is a cardinal principle of herpesvirus latency and reactivation. ### Mnemonic: "SACRAL for SEXUAL" **SACRAL** = Sacral ganglia store HSV-2 (genital/sexual herpes) **TRIGEMINAL** = Trigeminal ganglia store HSV-1 (oral/facial herpes)