Scabies
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  • (can survive 2-3 days off the human body) <br />
  • Scrap an unscratched burrow-------------- cover with a drop of immersion oil, -------------- scrap with a blade longitudinally along the length of the burrow or dermal curette & placed on a glass slide with a coverslip------- Under the lOx objective of the microscope, the female mite and/or her eggs or feces are seen <br />
  • in order to reduce the potential for reinfestation from fomites <br /> ensure killing of any nymphs <br />
  • A/R= burning, itching, numbness, rash, redness, stinging & tingling of the scalp <br /> can be used during pregnancy if indicated, with a shortened 2-hour application being sufficient <br /> Efficacy~ single dose, repeated Rx = 89 – 100%(average 98 <br /> A/R= pruritus,irritation, redness, swelling , ACD, seizures <br /> Note: <br /> Resistance is fairly common <br /> Not applied to raw areas or eyes <br /> Repeated application is required <br />
  • Pentathionic acid, which is toxic to fungi, is also formed by cutaneous bacteria <br /> 4(BBB)-drug shouldnot be used in children younger than the age of 5 years or weighing less than 15kg, or during pregnancy or lactation <br />
  • 5) Crotamiton <br /> a 10% lotion & cream, thin layer nightly treatments for 3-5 days <br /> M/A= not known <br /> Crotamiton relieves itching by producing what is called a counter-irritation <br /> Efficacy= is less effective than all of the other scabicides~ 40% <br /> in whom lindane or permethrin is contraindicated <br />
  • Treatrment should be directed to prevent spread of the scabies, <br /> may be harbouring the scabies mite during the asymptomatic incubation period. <br /> prevent re-infection with fomites, bed <br /> sheets, pillow cases, towels, and clothes <br /> worm during the past 5 days should be washed and boiled. <br /> fomites should be vaccumed <br />
  • - Scratching causes inflammation and secondary bacterial infection, with pustules, crusting, and cervical adenopathy <br /> -Posterior cervical adenopathy without obvious disease is characteristic of lice <br /> -&apos;plica polonica&apos;, -matt <br />
  • In chronic untreated cases (‘vagabond’s disease’) the skin becomes generally thickened eczematized and pigmented; lymphadenopathy is common. <br /> “morbus errorum” post inflammatory process <br />
  • lack of involvement of the hands and feet <br /> lack of involvement of the hands and feet <br />
  • Transmission occurs when contaminated fecal pellets are scratched into the bite site or excoriated skin <br />

Scabies Presentation Transcript

  • 1. Scabies & Pediculosis
  • 2. Infestation Infestation is the presence of animal parasites on or in the body, is common in tropical countries and less so in temperate ones. Infestations fall into two main groups: 1 those caused by arthropods; and 2 those caused by worms.
  • 3. Mechanisms of skin injury by arthropods Mechanical trauma Injection of irritant, cytotoxic or pharmacologically active substances Injection of potential allergens Invasion of the host's tissues Reactions to retained mouthparts Secondary infection
  • 4. HISTORY 2500 yrs  Sarcoptes scabiei is derived from the Greek words sarx (the flesh) koptein (to smite or cut) and the Latin scabere (to scratch).  first ascribed to the mite by Giovan Cosimo Bonomo in 1687.  Over 300 million people worldwide are infected
  • 5. EPIDEMOLOGY  women & children  urban areas,  winter  Prevalence 4 – 100%
  • 6. Transmission ◦directly by close personal contact, sexual or ◦indirectly via fomites  factors ◦overcrowding, ◦delayed treatment of primary cases, and ◦ public awareness
  • 7.  highly host-specific  an arthropod a member of the class Arachnida, subclass Acari, order Astigmata, and family Sarcoptidae.  Too small to be seen by the naked eye Adult female measures ~ 0.4 - 0.3 mm, & the smaller male 0.2 - O.15 mm
  • 8.  body is creamy white & is marked by transverse corrugations,  ovoid  four-pairs of legs - anterior two pairs end in elongated peduncles tipped with small suckers, In the female, the rear two pairs of legs end in long bristles, whereas in the male bristles are present on the third pair and peduncles with suckers on the fourth.  crawl at a rate of 2.5 cm/min, burrow through the stratum corneum at the rate of about 2 mm per day(0.5 - 5 mm/day)
  • 9.  number - <20 & with crusted scabies can be thousands to millions live mites can survive for up to a week in the environment, feeding on the sloughed stratum corneum  cannot fly or jump
  • 10. Pathogenesis F (within 20 min) burrows into the stratum corneum (traverses at a rate of 0.5 - 5 mm/day) avoid areas with a high density of pilosebaceous follicles
  • 11. Mating takes place once, and the female is fertile for the rest of her life (1 mo), Copulation in a small burrow---------the male, falls off the skin & perishes--------- Fertilized female enlarges the burrow using proteolytic enzymes to dissolve the stratum corneum of the epidermis ----- begins egg laying (3 eggs a day each) Six-legged larvae emerge from the eggs after 3- 4 days 90% of the hatched mites die
  • 12. Escape from the burrow by cutting through its roof------then dig short burrows called moulting pouches & transform into nymphs-------------After further moult into larger nymphs , adult males and females develop(in 2-3 weeks)
  • 13. Clinical features IP- 2-6 weeks  immediate symptoms –in re infection  Triad`s Pruritic papular lesions, Excoriations, and Burrows Site- The circle of Hebra ~ an imaginary circle intersecting the main sites of involvement - axillae, elbow flexures, wrists & hands, & crotch
  • 14. Cont...... Pruritis ○ accentuate at night & exacerbated by a hot bath or shower Primary lesions of scabies - burrows, papules, pustules, nodules, occasionally urticarial papules and plaques interdigital webbing of the hands, flexural aspect of the wrists, behind the ears, axilla, waist, ankles, feet, buttocks & belt area penile & scrotal in men, areola, nipples & genital area in women
  • 15. Distribution of lesions
  • 16. ◦In very young children, infants, elderly and immunocompromised hosts, a widespread eczematous eruption primarily on the trunk is common , scalp & face can also be affected.
  • 17. Contd... P/E The burrow ◦ pathognomonic sign and represent the intraepidermal tunnel created by the moving female mite. ◦ a 1-10 mm tunnel ◦ serpiginous, greyish-white thread-like elevations ◦ At the end of it a vesicle/pustule containing the mite may be noted, especially in infants & children at entry, slight scale
  • 18. In infants, commonly located on the palms & soles : F To identify burrows quickly: apply a drop of India ink or gentian violet to the infested area, remove it with alcohol Thin threadlike burrows retain the ink
  • 19. Contd...  Erythematous Papules & Vesicles (filled with serous fluid) rarely contain mites and most likely are due to a hypersensitivity reaction Papules= on the shaft of the penis & scrotum in men & on nipples in women Vesicles= on the palms & soles
  • 20.  Animal Scabies: Zoonotic scabies ◦ affect humans who come in close contact with the animal ◦ incubation period is shorter, the symptoms are transient ◦ usually manifests with vesicles & papules with atypical distribution ◦ Burrows are usually absent ◦ runs a self-limited course, require no treatment Mites from animals are not a source of human infestation, but they can produce bite reactions  Asymptomatic infestation ◦ not uncommon ◦ considered ‘carriers’
  • 21. Secondary scabies lesions With rubbing- secondary infection, - the host immune response against the mites and their products. Excoriations, Lichenification, widespread eczema, honey-colored crusting, postinflammatory hyperpigmentation, erythroderma, and frank pyoderma
  • 22. DDx Atopic dermatitis  Insect bites Contact dermtitis Autosensitization ('id' reaction) Drug eruptions  PPE
  • 23. VariantsVariants Nodular scabies  in 7-10% of patients with active scabies  Pink, tan, brown, or dull red nodules (2-20 mms)  May or may not itch  Persist on the scrotum, penis, and vulva and In neonates unable to scratch, pinkish-brown nodules may develop  usually sterile  Intralesional steroids, tar, or excision are methods
  • 24. DDx Nodular scabies  Papular urticaria (insect bites)  Prurigo nodularis  Secondary syphilis
  • 25. Bullous scabies Mimics BP both clinically & histologically (contain many eosinophils)  Vesicles and bullae-, particularly on the palms & fingers Immunofluorescent
  • 26.  In immunocompromised / debilitated patients, including those with: neurologic disorders, Down syndrome, organ transplants, graft-versus-host disease, adult T-cell leukemia, leprosy, or AIDS and institutionalized populations  Risk factors for profound infestation -an inability to mount an immune response, perceive pruritis, and/or physically scratch the skin Crusted scabies (Norwegian/hyperkeratotic scabies)
  • 27. * marked thickening and crusting of the skin. * Hyperkeratotic, crusted/scaling lesions teem with mites * large areas with prominent scalp lesions, hands and arms are usual locations * Swollen & crusted finger tips; & dystrophic nails * Pruritis- minimal/absent
  • 28. Contd... The rest of the skin usually appears diffusely xerotic highly contagious Severe fissuring & scaling of the genitalia & buttocks may be present Oral agent should be used in conjunction with a topical agent
  • 29. DDx Crusted scabies Psoriasis Seborrheic dermatitis
  • 30. Complications  Secondary impetiginization  Lymphangitis & septicemia ~ particularly in crusted scabies  Post-streptococcal glomerulonephritis  'post-scabietic pruritus‘ ◦ represent the body's response to dead mites that are eventually sloughed off (within 4 wks) along with natural epidermal exfoliation ◦ Tx- antihistamines or a short course of topical or oral corticosteroids
  • 31. Scabies and HIVfrequent unusual features head and neck occur with minimal or no pruritis but with an extensive papulosquamous eruption( i.e.,hyperkeratotic, Crusted scabies- soles - should arouse suspicion of underline HIV difficult to eradicate Oral ivermectin (200 1Micg/kg weekly) is the most effective
  • 32. Diagnosis  Mainly clinical Pruritus with typical lesions & distribution Contact Hx  Microscope ○Skin scrapings obtained from the finger webs, wrists, or ankles is most likely to be positive ○In Norwegian scabies, scraping of the thick scales will often yield several
  • 33. Dermoscopy PCR Biopsy
  • 34. Contd... H/pH/p  A patchy to diffuse infiltrate with eosinophils is noted in the reticular dermis  On transection, a scabies mite may occasionally be seen within the epidermis fragments of the adult mite exoskeleton serve as a clue to the Dx when mites, scybala or eggs are not identified
  • 35. Treatment Age cost severity ? previous treatment status  In infants with extensive involvement, several re treatments a week apart occasionally be required  second application of topical medication.......  Treat simultaneously all household contacts (even with no symptoms)
  • 36. Contd...
  • 37. Medications 1)1) Permethrin 5% cream applied for 8 -14 hrs standard first line topical scabicide  MoA= produce nerve paralysis & death in ectoparasites by causing delayed repolarization by disrupting Na+ current~ ovicidal 2) Benzyl benzoate(BBL)  Derivatives of balsam of peru 12.5% & 25% emulsion lotion overnight application for three consecutive nights or left to the skin for 48hrs  MOA= ?kills the adult scabies mite with yet unclear action  exerts toxic effects on the nervous system of the parasite, resulting toxic to mite ova, though its exact mechanism of action
  • 38. Contd... 3) Precipitated sulfur ◦ 6-10% precipitated sulfur ointment in a petrolatum base (for children 2.5%) ◦ Applied to the entire body for three successive nights~ 2wks MOA= kills adult scabies mite interact with cysteine, present in the stratum corneum, to form hydrogen sulfide--- safe in preg and neonates Efficacy = as high as 92% 4) ivermectin Structurally similar to macrolide antibiotics, MoA= blocks neurotransmission across nerve synapses that utilize glutamate or GABA(y- aminobutyrica cid) --- cause paralysis of peripheral motor function in insects Age specific
  • 39. Contd... Ivermectin dosage- 200 micg/kg; often the dose is repeated in 10 to 14 days LINDANE  1% lotion or cream  applied only in a thin coat to dry skin  should not be applied immediately after bathing  M/A= ?? Inhibits inositol in scabies mite to produce CNS excitation & death of the parasite  Inhibits GABA  C/I= children < 2 yrs of age, pregnant & lactation Weight --
  • 40. Follow-up visits  In 2 weeks is important to ascertain success or failure of therapy  Any new lesions  'post-scabietic pruritus‘ body's response to dead mites- till 4th week after treatment.  steroids
  • 41. Prevention
  • 42. Pediculosis  Phthiraptera family  Order Anoplura-blood-sucking (***solenophages) ectoparasites of mammals  Pediculus capitis, the head louse  Pediculus humanus, the clothing or body louse &  Pthitrus pubis, the pubic or crab louse  ingest blood, & produce skin lesions by mechanical puncture( stylet, haustellum) & injecting toxic secretions
  • 43. Pediculosis Capitis Head lice in school-aged children, 3-12yr, 10%of children : F affect all levels of society & all ethnic groups ◦Prevalence= 6 to 12 million infestations/year ◦incidence is low among African Americans ◦spread by close physical contact ◦sharing of head gear, combs, brushes, & pillows
  • 44. Etiology & Pathogenesis  is 1 to 2 mm long,  elongated,  greyish white flattened dorsoventrally, &  wingless  three pairs of sharp clow- grasp hairs and for feeding  feed approximately five times each day  5 - 10 eggs a day  can travel up to 23 cm/min  The larva, called a nymyh/instar, looks like a miniature adult louse  1 - 2 days (4 days) away from the scalp (Nits up to 10 days)  30 days  *Head lice do not carry or transmit any human disease.  hatches in 8 to 10 days, and reaches maturity in approximately 18 days. Nits are .8mm, with operculum
  • 45. Clinical findings  Louse - occipital and retro auricular regions ◦ <20 but in 5% >100  Itching or can be asymptomatic ◦ a result of hypersensitivity reaction to the saliva & faecal matter produced by the louse during feeding ◦ Sensitization - 3-8month  hemorrhagic crust  Excoriations, lymphadenopathy, & conjunctivitis(redness &swelling) may be observed
  • 46. Contd...Diagnosis  Identification of live adult lice, immature nymphs, and/or viable-appearing eggs  Live nits(egg cases) placed in close proximity to the scalp(parietal & occipital)  Have proteinaceou sheath ◦ cemented to the hair shaft with chitinous material secreted by the female accessory glands C0MPLICATIONS  Excoriation ----- Secondary bacterial infections
  • 47. DDx  Seborrheic piedra  Delusion parasitosis  Artifacts on the hair  Hair casts (pseudonitis)
  • 48. Pediculosis corporis (Body/clothing lice) EPIDEMIOLOGY  low of socio-economic  in urban public hospitals  No predilection for race, age, or sex  contaminated clothing or bedding
  • 49. ETIOPATHOGENESIS  Body Iouse/P. humanus var humanus  lifespan -18 days  270 to 300 ova  2-4mm  3 day,with out meal  comes to the surface only for meal
  • 50. CLINICAL FEATURES  linear excoriations primarily  Occasionally, a macula ceruleae (Iiterally, sky- blues pot) ◦a blue to slightly slate-colored macule.............bruise-like lesion (~1.5 cm) & often with a central punctum 2nd to altered blood pigments in clothing binds (waistband, buttocks & thighs) & is asymptomatic to slightly pruritic
  • 51. Contd... Diagnosis  examining the lining of the clothing seams for the presence of nits  By shaking out the clothing over a sheet of newsprint,  Nits that contain an unborn louse fluoresce white.  Nits that are empty fluoresce gray.
  • 52. DDx  Scabies  AD  ACD  Drug reaction  Viral exanthem  Systemic cause of pruritus
  • 53. COMPLICATIONS  Excoriation  secondary infection with S. aureus, S. pyogenes & other bacteria (impetigo & furunculosis)  act as vectors for R.prowazekaii (epidemic typhus), Bartonella quintana (trench fevers or endocarditis) & Borrelia recurrentis (relapsing fever)
  • 54. Pediculosis pubis (Pubic Lice) EPIDEMIOLOGY  most often are a sexually transmitted disease  ~ 30 % of patients have another concurrent STI  from one sexual exposure with an infested partner is more than 90%  contaminated clothing, towels, or beddings
  • 55. ETIOPATH0GENESIS  Pthiridae  crab - naming  second and third pairs of -to cling on to hair (pincer like claws)  light brown  0.8 to 1.2 mm in length  ambulate up to 10 cm/day  lifespan of 2 wks  25 ova
  • 56. CLINICAL FEATURES  Pruritus  Maculae ceruleae (sky-blue spots, (tache bleu), on inner thighs or sides of trunk  Bullous lesion  adult organisms on the body ( ~ 10 - 25 or more) pubic hair, any hair bearing site can be affected, eyelashes ((phthiriasis palpebrarum ○ in hirsute ~ short hairs of the thighs, trunk, & perianal area  nits near the base of the hair the duration of infestation can be approximated by the distance
  • 57. Contd... Diagnosis  louse in the pubic area  coexisting STI  microscopic examination Empty nits may indicate a prior infestation COMPLICATIONS  excoriation  Secondary infection -lymphadenitis & fever . generalized exanthem (pityriasis rosealike pediculid).
  • 58. DDx  Scabies  Extensive excoriation  Contact dermatitis  White piedra  Trichosporon cutaneum  Trichomycosis pubis  Hair casts
  • 59. Treatments PYRETHRIN (SYNERGIZED/SYNTHETIC= PERMETHRIN/PIPERONYL BUTOXIDE) 1%, 5% SHAMPOO Block Na+ channel repolarization Topically for 10min, repeat a wk later for body louse 100% cidal- 10min PERMETHRIN 1% CREAM ◦ Topically 8 -12 hrs repeat in 7 -10 days ◦ Currently treatment of choice for body louse
  • 60. MALATHION 0.5% LOTION ◦Organophosphate cholinesterase inhibitor ◦Topically for 8-12hrs (20-30min) LINDANE SHAMPOO 1% ◦Organochloride acts as GABA inhibitor ◦Topically for 5-10min, not to be repeated
  • 61. Contd...  Ivermectin, oral Inhibit GABA release & cause respiratory paralysis 250micro gm/kg a week apart  not ovicidal  Wet combing  Occlusive or suffocation  Boiling of clothing (65 *C), bedding, & other possible fomites is ovicidal & lousicidal  cotimoxazole  acctylcholincsteraseinhi biting insecticides  Robi comb, Tea tree oil and lavender oil
  • 62. Eye tx thick layer of petrolatum twice a day for 2 weeks (interere respiratory function –block) mechanical removal cryotherapy flurescein 10-20% mercuric oxide physiostigmine ointment!!!!!!!!! Oral ivermectin argon laser photo therapy aqueous pediculicide
  • 63. Contd...  Patients with HIV/AIDS ◦have more severe infestations with p. pubis & ◦unresponsive to conventional therapy
  • 64. References EMEDICINE Rook's Textbook of Dermatology
  • 65. THANK U!
  • 66. Malathion, carbaryl and permethrin preparation are probably the treatments of choice now. They kill lice and eggs effectively; malathion has the extra value of sticking to the hair and so Lotions should remain on the scalp for at least 12 h, and are more effective than shampoos. The application should be repeated after 1 week so that any lice that survive the first application and hatch out in that interval can be killed.protecting against reinfection for 6 weeks.
  • 67. Intralesional steroids, tar, or excision are methods of treatment for this troublesome condition, termed nodular scabies. Sensitization majority of mites are found on the hands and wrists, Children have often gathered mites and ova under the nails when scratching.
  • 68.  Permethrin 5% cream (Elimite) is the most widely used medication for scabies. It is a synthetic pyrethroid that is lethal to mites and has low toxicity for humans.  Lindane (y-benzene hexachloride) is also effective, with a low incidence of adverse effects when used properly. Because of  the availability of less toxic agents, lindane is rarely used as  a first-line agent. In much of the world, benzyl benzoate and  10% precipitated sulfur in white petrolatum are used to treat scabies. The scabicide should be thoroughly rubbed into theskin from the neck to the feet, with particular attention given to the creases, perianal areas, umbilicus, and free nail edge and folds. It is washed off 8 to 10 h later. Clothing and bedlinen are changed and laundered thoroughly.  Crotamiton (Eurax) has a lower cure rate than other available agents.  When used, it should be applied on 5 successive nights and  washed off 24 h after the last use.
  • 69. it usually takes 2-6 weeks before the host's immune system becomes sensitized to the mite or its by product 'post-scabietic pmritus'. body's response to dead mites second application of topical medication is performed in order to reduce the potential for reinfestation from fomites as well as to ensure killing of any nymphs that may have hatched as a result of thesemi- protective environment within the egg that allowed them to survive
  • 70.  Lotions should remain on the scalp for at least 12 h,  and are more effective than shampoos. The application  should be repeated after 1 week so that any lice  that survive the first application and hatch out in that  interval can be killed.  A systemic  antibiotic may be needed to deal with severe secondary  Infection  a head louse repellent,  containing 2% piperonal, is available over the  counter and may be worth a trial for those who are  repeatedly reinfested. Systemic ivermectin therapy is  reserved for infestations resisting the treatments listed
  • 71. th e head and body lice may be variants within a single species, but are thought by most biologists to represent two distinct species that can hybridize or interbreed under special circumstances.
  • 72. peri pilar keratin casts ('pseudonits'; hair muffs) [21,221 or dried globules of cheap hair lacquer. The acctylcholincsteraseinhibiting insecticides malathion and carbaryl (carbaril) Robi comb, co-trimoxazole, Tea tree oil and lavender oil prophylaxis
  • 73. Treatment failure  Evidence the presence of adult organisms  should be suspected if live lice are still present 12 to 24 hours after treatment  Failure to follow instructions  changing formulations,  dilution of the pediculicide  subtheraputic doses or duration  Neglecting to treat sexual contacts  Treating only the pubic area in hairy individuals  Re-infestation