A young 8-year old boy presents with multiple discrete, shiny, pin-head papules on dorsal aspect of hand, forearms and shaft of penis. The diagnosis is:
Correct Answer: Lichen nitidus
Description: Ans. d. Lichen nitidus (Ref: Mark Lebwoht 2/e p345)A young 8-year-old boy presents with multiple discrete, shiny, pin-head papules on dorsal aspect of hand, forearms and shaft of penis. The diagnosis is Lichen nitidus.FeatureLichen NitidusMolluscum contagiosumLichen planusSymptomsAsymptomaticAsymptomaticItchy (marked)Cutaneous lesion* Multiple, discrete (or closely grouped), minute, pinpoint to pinhead sizedQ (1-2mm), flat/ round or dome shaped papule with a glistening (shiny surface)Q* Papules are flesh colored or pink or shiny hypopigmentedQ (in blacks)* Extremely small, pinkJshiny pearly white/or flesh-skin coloredQ, dome shaped hemispherical papules with a characteristic central dell or umblicationQ* Containing a grayish central plug (pore) and white curd like substanceQ* It may enlarge slowly* Larger, plain (flat) topped, polygonal, pruritic, pink/purple (violaceous) papuleQWickham's striaeAbsentAbsentPresentQGroupingPresentQPresentQUsually notMucous membrane involvementUncommonNot commonCommonQ (Variably present)Site* Most frequently on flexural surfaces of upper extremities i.e. arm, forearm, wrist and dorsal surface of hands, lower abdomen, breast, the glans and shaft of penis and other areas of genital regionQ* Intertriginous sites such as axillae, popliteal fossa and groinQ.* Genital and perianal lesions can develop in children and mostly are non-STD* Hypertrophied, hyperplastic epidermisQ with intact basal cell layer.* Above the basal layer, enlarged cells containing large intracytoplasmic inclusions (Handerson - Paterson bodies) are seen.* Flexures (wrist), extremities (shin), lower back and genitalsQGrouped pinhead lesions on elbow. abdomen, penis and dorsum of hand in a child as shown in the picture is highly suggestive of lichen nitidus.Lie hen scrofulosorum is an uncommon asymptomatic lichenoid eruption of minute papule occurring in children and adolescents with strongly positive tuberculin reaction. It mainly involves perifollicular distribution on abdomen, chest, back and proximal limbs. A hallmark is that superficial epitheloid dermal granuloma surround hair follicles and sweat ducts and may occupy several dermal papillae. Lichen NitidusLesion and etiology are similar, but size is smaller 1.2 mm (pinhead sizeQ)Occurs as grouped lesions on elbow, abdomen, penis and dorsum of handQMucosal or nail changes are rareSelf limiting, non-itchyQHistopathology:Dense, circumscribed and distinctive infiltrate of histio-lymphocytic cells situated directly beneath thinned epidermis results in widening of papillary dermis with elongation and the appearance of embracement by neighboring rete ridges ( Ball in clutch appearanceQ).Thinned epidermis demonstrates central parakeratosisQ, variable /focal hyper keratosis without hypergranulosis, minimal hydropic degeneration and few dyskeratotic cellsTreatment:Antihistaminics particularly AstemazoleQ is effective. Lichen ScrofulosorumLichen scrofulosorum is a lichenoid eruption of minute papulesQOccurs in children and adolescents with tuberculosis.Pathogenesis:Usually associated with chronic tuberculous disease of the LNs and honesQClinical Features:Eruption is asymptomatic and is usually confined to the trunkQ.Lesions consist of symptomless, small, firm, follicular or parafollicular papules of a yellowish or pink color with flat-top or bear a minute homy spine or fine scales on their surfaceQ.It mainly involves perifollicular distribution on abdomen, chest, back and proximal limbsQ.Histopathology:A hallmark is that superficial epitheloid dermal granuloma surround hair follicles and sweat ducts and may occupy several dermal papillaeQ.Treatment:Antituberculous therapy results in complete resolution within a matter of weeksQ.FeatureLichen NitidusLichen planusSymptomsAsymptomaticItchy (marked)Cutaneous lesionMultiple, discrete (or closely grouped), minute, pinpoint to pinhead sizedQ (1- 2mm), flat/ round or dome shaped papule with a glistening (shiny surface)Q.Papules are flesh colored or pink or shiny hypopigmentedQ (in blacks)Larger, plain (flat) topped, polygonal, pruritic, pink/purple (violaceous) papuleQWickham's striaeAbsentPresentQGroupingPresentQUsually notMucous membrane involvementUncommonCommonQ (Variably present)SiteMost frequently on flexural surfaces of upper extremities i.e. arm. forearm, wrist and dorsal surface of hands, lower abdomen, breast, the glans and shaft of penis and other areas of genital regionQFlexures (wrist), extremities (shin), lower back and genitalsQScabiesInfestation caused by Acarus or Sarcoptes scabieQUsually a disease of children, with no gender predilectionMainly involving lower socio economic strata living in poor hygiene and crowdingTransmitted by close physical contact from human to human or from pets to human.Thus there are often several cases in same householdEpidemiology:Incubation period: 2-4 weeksQMC symptom: Itching (worse at night)Family history of similar itchy eruptions in close contactQMorphology of lesions and variants:Primary lesions are of three types:Burrow: Serpentine (S-shaped) path traversed by parasite in stratum corneumQ. It is pathognomic of lesion Papules and papulovesicles: Due to hypersensitivity to the mite Fine pin head size follicular papulesSecondary lesions:Pustules due to 2deg infection is one of commonest form of presentationEczematized exudative crusted lesions, in infants and children are predominant lesionsNodular lesions are seen on scrotumQ (MC), groin, and anterior axillary fold (Nodular scabies)Variants/Types:Crusted Norwegian scabies is most severeQ form seen in immunocompromised or mentally ill patients, and showing hyperkeratotic crusted lesions on whole body.Scabies incognetio is wrongly treated with steroids.Site of predilection:In adults web of fingersQ, flexure aspect of wrist, ulnar aspect offorearm, anterior axillary fold, umbilicus, periumbilical fold, genitalsQ (penis and scrotum in males, nipple and areola in females), upper thigh, lower part of buttocks Back is rarely affectedScalp, face, palms and soles are characteristically spared in adultsQ.In Infants, scalp, face, palms and soles are typically involvedQ.An anatomical circle, encompassing the axial, elbow flexures, wrists, hands, and genital region has been referred to as the circle of Hebra.Site of predilection for scabies is circle of HebraQ.Scabies and scabies in circle of hebra (both) simulate sabra dermatitis seen in prickly pears (eg. cactus with spines and glochids) pickers.TreatmentDrug of choice: PermethrinQ (1st) > BHCQ (2nd)Oral drug (only): IvermectinQOther drugs: Benzyl benzoateQ 25%, CrotamitonQ 10%, Malathion, MonosulfiramIn 2deg infection: IV antibioticsScabicides should be applied to the whole body (below jaw line in adults) to all members of family whether symptomatic or notQOrdinary laundering of cloths and bed linen. Mites any way die in unworn clothes in ~ 7 days.
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