SCABIES Awajo.pptx
- 2. Scabies Sarcoptes scabei var hominis: specific for humans Sarcoptes scabei var canis: animal mite, rarely causes infection in humans Tramsmission 1. Acquired through direct, prolonged, skin-to-skin contact with an infected person(i.e., same household). 2. Sexual contact. 3. ?Fomite ( infected clothing, bedding)
- 3. Female lifespan 46 weeks; lays 4050 eggs. Lays 3 eggs per day in tunnels; eggs hatchin 4 days. Burrow 23 mm daily, usually at night, and lay eggs during the day. Hatched larvae migrate to skin surface and mature into adults. Males and females copulate. Gravid female burrows back under stratum corneum; male falls off skin.
- 4. Epidemiology Estimated at 300 million cases/year worldwide. Epidemics ocured in 15 year cycles, latest 1960 Children (often 5 years). Nodular scabies more common in children. Young adults (body contact). Elderly and bedridden patients
- 5. Pathogenesis Hypersensitivity of both immediate and delayed types occurs in the development of lesions other than burrows. First infestation: For pruritus to occur, sensitization to S. scabiei must take place -takes several weeks to develop if 1st infestation. Reinfestation: After reinfestation, pruritus may occur within 24 h
- 6. Clinical features Pruritic papular lesions- Intense, widespread, usually sparing head and neck. Lesions at Site of Infestation Intraepidermal Burrows-grey, slightly elevated Scabietic (Scabious) Nodule Hyperkeratosis/Crusting Psoriasiform Hypersensitivity lesion: Small erythematous papules / papulovesicles Persistent nodular lesions (penis) Secondary changes Pustules: due to secondary infection Eczematised : common infants, children
- 7. Sites Burrows finger webs, sides of finger, flexural aspects of wrists, feet, male genitalia Hypersensitivity Excoriated papules, papulovesicles Infants: scalp, face, palms, soles Line Of Hebra
- 8. R.H., a 26 year old woman comes to see you with a seven week history of a rash which is worse on her hands. It is extremely itchy, particularly at night. She is worried that she could give this itching to her 4 year old son
- 10. Diagnosis of scabies is made by looking at the burrows or rash. Confirmation of diagnosis Skin scraping papule/ pustule microscopy : mites, eggs, or feces
- 11. Treatment TOPICAL 5% permethrin : apply for 8 hours on days 1 & 8 1% GBHC: apply for 8 hours on days 1 & 8 25% Benzyl benzoate: 3 application for 12 hourly 10% Crotamiton: apply for 8 hours on days 1,2,3 & 8 10% Precipated Sulphur: twice daily for 14 days; DOC in pregnancy 1% Lindane Solution-Apply only once. Wash off in 8 to 12 hours. ORAL Ivermectin 200亮g/kg body weight on day 1, 8 and 15
- 12. General principles 1. Apply to whole body below jaw line including genitals, soles, under free edge of nails 2. Treat all family members simultaneously 3. Ordinary laundering of linen 4. Antihistamines: for 4-6 weeks 5. Persistent nodular lesion topical steroid may be required
- 13. Norwegian scabies or crusted scabies Immunocomprised patients Mentally challenged The number of infesting mites may be >1 million. C/F: widespread crusted, hyperkeratotic lesion Innumerable mites (hundreds) Very contagious Treatment - Topical 5% permethrin or topical 5% benzoyl benzoate applied daily for seven days, then twice weekly until cure Keratolytic creams on alternate days to scabicide Oral ivermectin on days 1, 2, 8, 9, and 15 (add days 22, 29 if infestation is severe).
- 14. Animal scabies Mite - Sarcoptes Scabiei var Canis Transmission - Infected animal to human; human to human transmission does not occur Source horses, cattle, dogs, cats; (this infection in animals is called Mange) C/F small, pruritic papules temprorary no burrows site - front of trunk, medial aspect of upper extremities Treatment antihistamines specific antiscabetic not required
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