The histopathologic evolution of recurrent herpes simplex labialis

Area of Science:

• Dermatopathology
• Virology
• Histology

Background:

• Recurrent herpes simplex labialis, commonly known as cold sores, is a prevalent viral infection.
• Understanding the early histopathologic changes is crucial for diagnosing and managing this condition.

Purpose of the Study:

• To investigate the natural history of recurrent herpes simplex labialis through detailed examination of biopsy specimens.
• To identify the earliest cellular and tissue alterations associated with herpes simplex virus (HSV) infection in cold sores.

Main Methods:

• Hematoxylin and eosin (H&E) stained biopsy sections from cold sore lesions at various clinical stages were analyzed.
• Microscopic examination focused on cellular and nuclear changes within the epidermis and dermis.

Main Results:

• Earliest findings included epidermal nuclear changes: chromatin clumping, "ground glass" appearance, and nuclear ballooning.
• Cytoplasmic vacuolization in keratinocytes was an early alteration; eosinophilic intranuclear inclusions were rare and seen in later stages.
• Herpes-induced changes initiated focally in the basal layer, rapidly affecting the entire epidermis and pilosebaceous units. Dermal cells showed no typical HSV changes.
• Inflammatory infiltrate evolved from equal numbers of mononuclear and polymorphonuclear cells in early lesions to predominantly neutrophils in later stages.

Conclusions:

• Histopathologic changes of recurrent herpes simplex labialis originate multicentrically within the epidermis.
• These microscopic alterations are detectable prior to the appearance of clinical signs and symptoms of cold sores.