Skin nontumor

Lichenoid and interface reaction patterns

Pityriasis lichenoides et varioliformis acuta

Topic Completed: 1 August 2011

Minor changes: 19 March 2020

Copyright: 2002-2021,, Inc.

PubMed Search: Pityriasis lichenoides

Mowafak Hamodat, M.B.Ch.B., M.Sc.
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Cite this page: Hamodat M. Pityriasis lichenoides et varioliformis acuta. website. Accessed September 19th, 2021.
Definition / general
  • Also called PLEVA, Mucha-Habermann disease
  • Overlaps with pityriasis lichenoides chronica
  • Sudden onset of crops of small, ulcerated papules on trunk
  • May heal with superficial scarring resembling variola (smallpox)
Microscopic (histologic) description
  • Acute lesion shows epidermal changes with much exaggerated scale; marked inter- and intracellular edema accompanied by keratinocyte necrosis and interface changes
  • Exocytosis is usually prominent and intraepidermal red blood cells are characteristic
  • Upper dermis is edematous and contains wedge shape of lymphocytes and histiocytes, usually perivascular, varies from sparse to dense; prominent red cell extravasation
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