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Summary of Treatment

Lichen Planus

  1. Definition
    Acute or chronic inflammation of mucous membranes or skin characterized by violaceous, shiny, pruritic papules topped with Wickham’s striae (fine white lines); milky white papules in mouth
    1. Sites: most common –around wrist and ankle
    2. Scalp lesions associated with scarring alopecia [ Lichen plano pilaris]
    3. spontaneously resolves in weeks or lasts for years (mouth and shin lesions)
    4. Mnemonic “5 P’s: Purple, Pruritic, Polygonal, Plain-topped, Papules,
    5. Precipitating factor: severe emotional stress During the acute phase, new papules may appear at sites of minor skin injury, such as a superficial scratch (Koebner's phenomenon). Hyperpigmentation (and sometimes atrophy) may develop as lesions subsides.

Associated with hepatitis C primary biliary cirrhosis, alcoholic cirrhosis, hepatitis B.

Nail change in Lichen planus
•  Pterygium
•  Red lunula
•  Anychia
•  Melanonychia
•  Onychorrhexis
•  Nail dystrophy
•  Longitudinal red line
•  Twenty-nail syndrome
•  Nail pitting

Twenty nail syndrome Seen in lichen planus, where all 20 nails are lost without any other evidence of lichen planus else where on the body.

  1. Treatment
    1. Topical corticosteroids with occlusion or intradermal  steroid injections
    2. Short courses of oral prednisone (rarely)
    3. PUVA for generalized or resistant cases
    4. Oral retinoids for erosive lichen planus in mouth

A recurrent, pruritic, inflammatory eruption characterized by small discrete polygonal flat-topped violaceous papules that may coalesce into rough scaly patches, often accompanied by oral lesions.

The cause is usually unknown. Some drugs (eg, arsenic, bismuth, gold) or exposure to certain chemicals used to develop color photographs may cause an eruption indistinguishable from lichen planus. Long-term use of quinacrine or quinidine may produce hypertrophic lichen planus of the lower legs and other dermatologic and systemic disturbances. Other causes include liver disease and graft-vs.-host disease.


Disorders showing Koebner's phenomenon
•  Lichen planus
•  Psoriasis
•  Vitiligo
•  Lichen nitidus
•  Molluscum contagiosum
•  Warts
•  Darrier disease (kertosis follicularis)
•  DLE
•  Pityriasis rubra pilaris
Rare causes are
•  Erythema multiforme
•  Hailey-hailey disease
•  Leukemia & Carcinoma
•  Lichen sclerosis
•  Necrobiosis lipoidica
•  Xanthoma
•  Vasculitis

Characteristics of scales in various papulosquamous disorders
Psoriasis - Silvery scales
Pityriasis rosea - Collarette of scales on the leading edge
Seborrheic dermatitis - Greasy scales
Pityriasis lichenoides chronica - Mica-like, adherent scales

Morphology of papules/plaques in various papulosquamous disorders
Psoriasis - Erythematous papules and plaques an extensors (elbow & knee)
Lichen planus - Violaceous papules with Wickham's striae an flexural surface
Pityriasis rosea - Annular plaques on Trunk
Seborrheic dermatitis - Yellowish, follicular papules on scalp and face
Pityriasis rubra pilaris - Erythematous follicular papules on Trunk & dorsum of hand
Secondary syphilis - Dusky erythematous papules
Pityriasis lichenoideset varioliformis acuta - Erythematous edematous papules surmounted by vesicles/crust
Scaling is absent or minimal
  1. Flexures (Groins, axillae, infra - mammary folds, vulva, gluteal cleft) 
  2. Glans in uncircumcised patients (in circumcised patients scales are present on glans) 
  3. Guttate psoriasis
Not found in psoriasis 
  • Alopecia (despite the involvement of scalp) 
  • Face involvement (though scalp lesion can extend on foreheaD. 
  • Mucosal involvement
Uncommon in psoriasis
  • Joint involvement (5-10%) 
  • Pruritus
Isomorphic phenomenon Pseudo-isomorpbic pbenomenon
Psoriasis (characteristiC.
Lichen planus
Kaposi SA
Mollscum Contagiosum
Discoid lupus Erythematosus
Plane warts
Molluscum contagiosum
Eczematous lesions


Summary of Important Papulosquamous Disorders

Table Papulosquamous Disorders

Clinical features

Other Notable Features

Histologic Features








Lichen planus





Sharply demarcated, erythematous plaques with mica-like scale: predominantly elbows, knees, and scalp; atypical forms may localize to intertriginous areas; eruptive forms may be associated with infection (Reiter’s syndrome)

Purple polygonal papules marked by severe pruritus; lacy white markings, especially associated with mucous membrance lesions

Rash often preceded by herald patch; the trunk, and eruption lines up in skin folds giving a “fir tree”-like appearance; generally spares palms and soles

May be aggravated by certain drugs, infection; severe forms seen associated with HIV

Certain drugs may induce:

Thiazides, antimalarial drugs


Variable pruritus; self-limited resolving in 2-8 weeks; may be imitated by secondary syphilis

Parakeratosis, Munro’s microabscess





Basal-cell degeneration Band like T- cell infiltrate in dermis

Pathologic features often nonspecific

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