Circle of hebra is associated with

Scabies Causative agent: sarcoptes scabiei var hominis Most common age:1- 5 years children are commonly effected Herd immunity is present Infected individual: feilised female establishes infection Factors responsible for transmission of infection: Close contact for 15-30min High humidity and low temperature our survival. Overcrowding Clothing,bedding,fomites-less common for transmission Female mite burrows into skin and lays eggs and dies after days Eggs hatch to larva and reach maturity Favourable sites for mites- lesions appear- circle of hebra Web spaces of hands Volar aspect of wrists Elbows Axillae Groins Scrotum Shaft of penis Areola in females Umbilicus and periumbilical area Genital area Inner thigh and buttocks Areas spared- face high density of hair follicles Infants- face ,scalp, palms and soles typically involved Clinical features: Itching predominant symptom-worst at night Excoriated papules in the characteristic sites, pustules Burrows are the characteristic lesions- pathognomic of scabies It is a serpentine thread like greyish dark line-tunnel in the stratum corneum that host a a parasite Various other types of scabies Scabies in babies vesicles over Palma and soles, scalp and face are involved. Often pyoderma is present Nodular scabies Crusted scabies- Norwegian scabies- hyperkeratotic scaly crusted lesions with large number of mites. Seen in patients with neurological deficits ,mental retardation, low immunity,malnutrition,tuberculosis,diabetes mellitus,dementia, hiv, immunosuppressive therapy Complications Secondary bacterial infection Acute glomerulonephritis Treatment-anti scabicidal drugs Gama benzene hexachloride 1%lindane 12 -24 hrs a day/2hrs in children Permethrin 5%cream -8-12 hrs at night. It act on the nerve cell membrane and disrupt sodium channel current Benzoyl benzoate 25%emulsion left on body for 48hrs or 3 consecutive nights Crotamiton 10%lotion every night for 2days Malathion 0.5% liquid 6%precipitated sulphur Ivermectin 200ug/kg two doses at 10day interval GABA agonist and chloride channel opener IADVL textbook of dermatology page 429