42-year old female experienced recurrent eruption of small grouped vesicles of the skin of the back of the left hand (excision of affected skin).
- Three sections of the skin are shown.
- In two, irregular intraepidermal vesicles encompassing the full thickness of the epidermis are seen. Viral cytopathic effects cause progressive hydropic swelling of epidermal cells, with eventual rupture of cells and marked acantholysis (reticular degeneration).
- Vesicles are filled with numerous multinucleated giant cells, keratinocytes with basophilic round to oval intranuclear inclusions surrounded by a clear halo and keratinocytes displaying ballooning degeneration. Besides, few inflammatory cells and a serous exudate are present.
- The underlying dermis exhibits a marked edema and partly a dense lymphocytic infiltrate accentuated around small vessels. In addition, isolated extravasated erythrocytes are present.