A young lady presents with white lacy lesions in oral cavity and her proximal nail fold has extended onto the nail bed. What is the likely diagnosis?
Psoriasis
Geographic tongue
Lichen planus
Candidiasis
Ref: Papulosquamous Disorders. In: Thappa DM. editor. Essentials in Dermatology, 2nd edn., NewDelhi: Jay pee Brothers Medical Publishers (P) Ltd 2009:82-98.Explanation:LICHEN PLANUSIt is a pruritic, inflammatory papulosquamous disorder affecting the skin, mucous membranes, nails and hair follicles.Etiology - UnknownGenetic predisposition: HI A B8- oral LP: HLA-Bw 35-cutaneous LPExogenous: Primary biliary cirrhosis, alcoholic cirrhosis, hepatitis B, hepatitis CDrugs cause lichenoid drug eruptionsMetals like mercury (dental amalgams), palladium, gold - oral lichenoid eruptionsClinical features:30-60 years; children -4% of cases, childhood LP more common in India 05 SkinIntensely pruritic, flat topped, shiny, polygonal, violaceous papules and plaquesPredominantly flexor distribution - flexor of wrist, forearm, legs, trunk, glans penis (cf- psoriasis another papulosquamous disorder has predominant extensor distribution)Wickham fs striae- netw-ork of greyish w hite streaks on papules seen on pressing with glass slide after application of oil - corresponds to wedge shaped hvpergranulosis seen on histo-pathologyKoebner! isomorphic phenomenon commonAnnular LP- glans penisHypertrophic LP- shinsActinic LP-sun exposed areasOral:Classical type is reticulate pattern- white/ violaceous lacy reticular network of coalesent papules in buccal mucosa and tongue; usually asymptomaticMost common pattern - ulcerative/erosive LPNail:5-10% casesThinning of nail plate (cf psoriasis - thickening of nail plate), longitudinal ridging, roughening of nail plate (trachyonychia) and nail dystrophy involving all 20 nails called 20 nail dystrophy (also seen in alopecia areata)Classical/characteristic nail finding (but not common finding)- pterygium formation (proximal nail fold fuses with nail bed)Hair follicles: lichen pktnopilaris - scarring alopeciaHistopathology:HyperkeratosisWedge shaped hypergranulosis (psoriasis - hypogranulosis)Irregular acanthosis (psoriasis - regular acanthosis)Saw tooth rete ridges (psoriasis - elephant foot/camel foot like/club shaped rete ridges ) Basal layer vacuolar degenerationBand like dermal lymphocytic infiltrate hugging epidermisMax Joseph spaces - subepidermal clear zone (subepidermal clear zone in lepro- matous leprosy is called Grenz zone)Melanin incontinenceTreatment - steroids (topieal/intralesionsal/ systemic), retinoids, cyclosporine, PUVA photochemotherapy, dapsone, methotrexateLichen planus- "8 P's"Papu losq uamous disorderPruriticPlane toppedPolygonal/polyangularPurple colouredPapulesPlaquesPigmentation after healing Pterygium formation in nails
Lichen Planus & Lichenoid Dermatoses