Herpes Zoster typically involves which distribution?

Herpes Zoster typically involves which distribution?

• A. Bilateral symmetric involvement
• B. Isolated oral mucosa involvement
• C. Generalized vesicular eruption
• D. Unilateral dermatomal distribution, usually thoracic nerve roots

Answer: (D)

Herpes zoster results from reactivation of latent varicella-zoster virus in a sensory ganglion. This inflammation affects the sensory nerve fibers of a single dorsal root, so the rash appears as a painful vesicular eruption that follows the fibers of one dermatome. Because it involves one ganglion, the distribution is unilateral and stays on one side of the body, typically with a belt-like pattern around the trunk. The thoracic dermatomes are the most commonly involved, though any dermatome can be affected (including trigeminal distribution in the face). That’s why the classic description is a unilateral dermatomal distribution, usually thoracic nerve roots. Bilateral symmetrical involvement, isolated oral mucosa involvement, or a generalized vesicular eruption do not fit the typical pattern of herpes zoster.

Herpes zoster results from reactivation of latent varicella-zoster virus in a sensory ganglion. This inflammation affects the sensory nerve fibers of a single dorsal root, so the rash appears as a painful vesicular eruption that follows the fibers of one dermatome. Because it involves one ganglion, the distribution is unilateral and stays on one side of the body, typically with a belt-like pattern around the trunk. The thoracic dermatomes are the most commonly involved, though any dermatome can be affected (including trigeminal distribution in the face).

That’s why the classic description is a unilateral dermatomal distribution, usually thoracic nerve roots. Bilateral symmetrical involvement, isolated oral mucosa involvement, or a generalized vesicular eruption do not fit the typical pattern of herpes zoster.