Skin inflammatory (nontumor)
Lichenoid and interface reaction patterns
Lichen planus

Topic Completed: 1 August 2011

Revised: 26 March 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Lichen planus [title] skin "loattrfree full text"[sb]

Mowafak Hamodat, M.B.Ch.B., M.Sc.
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Cite this page: Hamodat M Lichen planus. website. Accessed January 27th, 2020.
Definition / general
  • Purple, pruritic and polygonal papules of unknown origin
Clinical features
  • Usually flexor arms and legs, glans penis and mucous membranes; may be confined to oral mucosa
  • Self-limiting, lasting 1 - 2 years, although longer for oral lesions
  • Rare in children in West, but more common in children in Asia and Middle East (Indian J Dermatol Venereol Leprol 2010;76:366)
  • May have zone of hyperpigmentation after resolution
  • May represent an abnormal, delayed hypersensitivity reaction to an unknown epidermal neoanatigen
  • Associated with hepatitis B and C, HIV, numerous drugs

  • Koebner phenomenon: new lesions at sites of trauma
  • Lichen planopilaris: primary site of involvement is the epithelium of hair follicles, causing alopecia
  • Wickham straie: white dots or lines within papules
  • Variants: atrophic, bullous, follicular, hypertrophic, pemphigoid and ulcerated
Clinical images

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Lichen planus on the arm

Microscopic (histologic) description
  • Classic example of a lichenoid dermatitis
  • Hyperkeratosis and acanthosis; prominent, granular cell layer, sawtoothing of rete pegs, bandlike chronic inflammatory infiltrate (T cells and macrophages) that destroys the dermoepidermal junction
  • Civatte bodies (apoptotic basal cells, PAS+)
  • Artifactual cleft formation between epidermis and papillary dermis
  • Occasional subepidermal bullae
  • No atypia
Microscopic (histologic) images

Contributed by
Hillary Rose Elwood, M.D.

Band-like lichenoid lymphocytic infiltrate with irregular saw tooth rete ridge, hypergranulosis and hyperkeratosis

 Contributed by
 Andrey Bychkov, M.D., Ph.D.
 Kameda Medical Center

Lymphocytic band

 Contributed by
 Amy Lynn, M.D.

Various images

Positive stains
  • Linear, fibrillar band of fibrin along dermoepidermal junction
  • The cytoid bodies may be highlighted by IgM, IgG, IgA and C3
Differential diagnosis
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