LICHENOID DERMATITIS
►Lichenoid (by clinician):
Papules & plaques resembling lichen (symbiotic growth of algae & fungi) stuck on the skin.
►Lichenoid (by pathologist):
A band-like infiltrate of inflammatory cells (mostly lymphocytes) in the superficial dermis, parallel to the epidermis.
►Lichen planus is both clinically lichenoid & pathologically lichenoid.
►Lichenoid (by clinician):
Papules & plaques resembling lichen (symbiotic growth of algae & fungi) stuck on the skin.
►Lichenoid (by pathologist):
A band-like infiltrate of inflammatory cells (mostly lymphocytes) in the superficial dermis, parallel to the epidermis.
►Lichen planus is both clinically lichenoid & pathologically lichenoid.
Lichen planus is distinctive inflammatory dermatosis characterized by pruritic violaceous papular lesions which can involve the skin, mucous membrane, hair and nail.
5 ‘P’ s of LICHEN PLANUS
►1. PRURITIC
►2. PURPLE
►3. PAPULAR
►4. PLANE TOPPED
►5. POLIGONAL
►6.Pleomorphic
►7.Postinflammatory hyperpigmentation
EPIDEMIOLOGY
►LP is worldwide in distribution.
►Incidence: 0.4% - 0.8%.
►Most common in 20 – 40 years age group.
►Very rare in children.
►More common in male than in female
.
CLINICAL FEATURES
Classical cutaneous lesion of LP: Intensely pruritic, violacious, polygonal, flat toped papules.
►Wickham’s striae: Early papules may show a radiating pattern of white streaks within the lesion, called wickham’s striae best seen on the surface of the lesion after mineral oil is applied.
►Koebner’s phenomanon: The Koebner’s phenomenon (isomorphic response) is seen as a reaction to trauma such as scratching.
►The lesions are usually bilaterally symmetrical over the flexural surfaces of the extremities.
►The wrists and ankles are favored locations for lichen planus, but any part may be affected, including palm, soles and genitalia.
Clinical variants
@Hypertropic lichen planus
@Atrophic lichen planus
@Linear lichen planus
@Annular lichen planus
@Guttate lichen planus
@Follicular lichen planus
@Bullous lichen planus
@Ulcerative lichen planus
@Actinic lichen planus
ASSOCIATED CONDITIONS
Chronic active hepatitis (autoimmune and postviral) and Primary biliary cirrhosis.
Ulcerative colitis, A.A, vitiligo, morphoea, dermatomyositis, SLE, myasthenia gravis.
Recently, Hepatitis C virus has been implicated in triggering lichen planus.
DIFFERENTIAL DIAGNOSIS
Pityriasis rosea
Psoriasis
Lichen simplex chronicus
Lichenoid (LP-like) eruptions
THERAPY OF CUTANEOUAS LICHEN PLANUS
►Corticosteroids (Topical, Intralesional, Systemic)
►Retinoids (Acitretin, Tretinoin, Etretinate)
►Photochemotherapy (PUVA Photochemotherapy)
►Immunosuppressive agents Cyclosporin(3-10mg/kg/day-- 4-6 weeks)
►Dapsone : 200mg/day 4 months.
►Antimalarials : 200-400mg/day (actinic LP)
►Metronidazole : 500mg BD 2 months.
►Combination therapy with tetracycline or doxycycline & nicotinamide.
►Azothioprine, Cyclophosphamide, Methotrexate: Cytotoxic effect on proilferative lymphoid tissue.
►Low molicular wt. Heparin in low doses has lymphoid antiproliferative & immunomodulatory.
3mg/wk – 4-6 weeks.
►Skin grafting in ulcerative LP of sole.
GENETIC DISORDERS:http://geneticdisordersofhuman.blogspot.com/
