Shingles characteristically presents with which pattern?

• A. Bilateral widespread rash
• B. Unilateral dermatomal distribution
• C. Palpable purpura on limbs
• D. Diffuse urticaria

Answer: (B)

Shingles classically shows a painful vesicular rash that follows a single sensory nerve segment, occupying a unilateral dermatomal distribution. This disease arises from reactivation of latent varicella-zoster virus in a dorsal root ganglion, so the eruption appears in one dermatome on one side of the body and does not cross the midline. The rash often begins with pain or tingling before the rash appears, then develops into grouped vesicles on an erythematous base that crusts over over the next week or so.

If the rash were bilateral and widespread, it would suggest disseminated disease or another condition like primary varicella (chickenpox) rather than classic shingles. Palpable purpura or diffuse urticaria point to vasculitis or hypersensitivity reactions, not the typical dermatomal vesicles of shingles.