In HSV (...) endoscpy shows small, discrete, punched out, superficial ulcerations with or without fibrinous exudation. In later stages, a diffuse erosive esophagitis develops from enlargement and coalescence of the ulcers.

Mucosal cells from a biopsy sample taken at the edge of an ulcer show balloning degeneration, ground-glass changes in the nuclei with eosinophilic intranuclear inclusions (cowdry type A).