Ans: B (Face) Ref: Nelson Textbook of Pediatries, 19th ed.Explanation:SCABIESScabies is a contagious disease caused by a miteFamily: SarcoptidaeClass : Araehnida2 Main types: Human scabies and animal scabiesCausative organism: sarcoptes scabiei var ho min isMorphologyCreamy white, ovoid bodySize : 0.4x0.2 (female) , 0.2 x 0.15mm (male)Time from hatching to adult : 14-17 daysAverage rate of egg laying: 2-3/ day, (40-50 eggs/ lifetime)Average number of female mitesIn adult : 12In infant: 20Lifespan of adult female mite : 4-6 weeksIncubation periodI ST episode 4 weeksSubsequent episode ->> 2 weeksHow is scabies transmitted?Scabies is passed from an infected person to another via prolonged skin contact, sexually and nonsexually (ten minutes or more, often through hand holding)Infected persons who have no itching can pass the mite on to othersA person can be infected for up to 2 to 6 weeks before the rash or itching occursScabies is not transmitted via clothing or beddingClinical FeaturesNocturnal itchingPathognomic lesions are burrows - slightly raised, brownish, tortuous lesionsBurrow's can be difficult to identify but absence of burrow's does not exclude scabiesUsual sites are wrist, borders of hands, sides of fingers, finger web spaces, instep of feet & genitalia.Papular rash.The rash is an allergic reaction of the body to the mite, its waste products, and its eggs.Sites of rash may not correspond to sites of burrows.Classical sites (Circle of liebra)Axilla, Elbows, Wrist, Hands, Crotch, -- all forms a circleOther variantsNodular scabies- scrotum, axilla, groins, penisBullous scabiesCrusted scabies (Norwegian)Neurologic disorders, immunocompromised patientswidespread erthema, hyperkeratosis, crusting without burrow'sInnumerable mitesScabies in cleanScabies incognitoScabies in infants and children:Face, scalp.palms and solesPapules, vesicles, nodules in atypical distributionScabies in elderly:Atypical,back is commonly involvedScabies in hiv/aids:Crusted & atypical varieties seenComplicationsSecondary infections: staphylococcus aureus, streptocooci.EczematizationGlomerulonephritisUrticariaDiagnosisHistory wiseH/o nocturnal itchingFamily history of itchingTypical lesions and their localizationDiagnostic methodsDirect examinationScrapping & examination mineral oilProbing of burrow with toothpickIndia inkDermoscopyPCRAntiscabicidal agentsTopical agentsPermthrin 5% cream.Lindone (gamma benzene hexachloride) 1 % lotion or cream.Benzyl benzoate 10% and 25% lotion or emulsionMalathion 0.5%' lotion.Manosulfiram 25% lotion.Crotamition 10% cream.Precipitated sulphur 2%-i0% ointment.Esdepallethrine 0.63% aerosol.Ivermection 0.8% lotion.Oral drugIvermection.Symptomatic relief of itchingsedative H1 antihistaminicsTreatment of secondary infections and eczematizationPrior to antiscabietic treatment, this should be treated appropriatelyScabies in infantsSulphur 2%-l0% in petrolatumPermethrin 5% cream is approved for use only in infants older than 2 months.Ivermectin and lindane are contraindicatedin infantsPermethrin 5% cream is the most effective and safe modalityBenzyl benzoate can be diluted to 12.5% emulsion and used topically.Scabies in pregnant and lactating women6% sulphur precipitate is recommended.Ivermectin, permethrin. and lindane are contraindicatedCrusted scabiesIvermectin is the drug of choice hut multiple doses plus topical agents may be required.The hyperkeratosis is treated with a keratolytic agent (5%-10%' salicylic acid in petrolatum).Nails are cut short and brushed with a scabicidal agent.A cure is obtained after a mean treatment of three weeks.Nodular scabiesAntiscabitics followed by intralesional steroids