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2013-06-06 14:21:26
skin eye infections

chapter 18
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  1. structure of the skin - intact barrier
    • epidermin - avascular, includes many layers of dead cells, epithelial
    • dermis - vascular, connective tissue
  2. skin natural protection
    • sweat - contains salt, acids (ph of skin ~ 5), and lysozyme (anti microbial)
    • tears - lysozyme
    • sebum - oil, breaks down into fatty acids that are antimicrobial
  3. normal microbiota of skin
    • Gram negatives - pseudomonas (likes warm moist environment), janthinobacterium
    • gram positives - staphylococcus epidermitis, staph aureus (moist, mucous membranes), strep species (mouth)
  4. bacterial infections of the skin
    • acne
    • impetigo
    • erysipelas
    • scalded skin syndrome
    • folliculitis
    • abscesses
    • cellulitis
    • necrotizing fascites
    • gas gangrene
    • leprosy
  5. acne
    • inflammed papules (bumps) or pustules (pus filled) on the skin
    • sebum becomes trapped in pores and bacteria feed on it
    • population increases and causes inflammation; more oil = more acne
    • cause: propionibacterium acnes - gram + bacillus
    • factors:  hormones, cleanliness
    • treatments:  topical or oral, UV
  6. impetigo
    • small break in skin becomes infected, crust over and ooze clear fluid
    • causes:  2 possible, both gram +.  1) strep pyogenes 2) staph aureus
    • treatment:  topical (bactroban or altabax), oral (cephalexin)
  7. erysipelas
    • deeper, enters via epidermis and gets into the dermis
    • symptoms:  red, hot, swollen, fever & chills if it enters blood
    • cause:  strep pyogenes
    • treatment:  penicillin
  8. scalded skin syndrome
    • red skin peels away
    • cause:  staph aureus; exfoliative toxins cause outer layers to separate and peel off
  9. folliculitis
    • inflammation of the hair follicle or glands
    • looks like chicken skin
    • cause:  staph, strep
  10. abscesses
    • accumulation of pus in a lesion (fibrous)
    • cause:  staph aureus
    • furuncle:  single follicle or gland; often buttocks, axillae, or on back of neck
    • carbuncle:  deeper and larger
  11. cellulitis
    • non pus forming infection of dermin and subcutaneous layer, can enter blood stream
    • lymphangitis:  red lines radiating from site
    • cause:  staph aureus or strep pyogenes (pus forming)
  12. necrotizing fascites
    • cause:  strain of bacteria that can break down connective tissue; very invasive
    • hyaluronidase:  breaks down connective tissue
  13. gas gangrene
    • myonecrosis:  destruction of tissue and muscle
    • produces large amounts of gas; foul smelling
    • cause:  clostridium perfringens- anaerobic spore forming bacillus; alpha toxin - RBC lysis, edema, tissue damage; collagenase & hyaluronidase - breaks down connective tissue
    • treatment:  large doses of penicillin
    • hyperbaric O2 chamber - lethal to organism
  14. leprosy
    • cause:  mycobacterium leprae - acid fast bacillus, slow grower, prefers cooler temp
    • two forms:  a) tuberculoid leprosy:  local, tubercle forms in skin, may cause nerve damage.  b) lepramatous leprosy:  systemic, extensive skin damage at the periphery
    • transmission:  nasal secretions and skin to skin; takes 3-5 years for infection to grow
    • treatment:  multi drug long term therapy; rifampin, dapsone and clofazimine
  15. viral infections of the skin - vesicular rashes
    • vesicular rashes - fluid filled vesicles
    • chicken pox
    • shingles
    • smallpox
    • monkey pox
    • fever blisters or cold sores
  16. viral infections of the skin - maculopapular rashes
    • maculopapular rashes:  don't fill w/ fluid, no vesicle, just raised pink/red bumps
    • measles (rubeola)
    • rubella (german measles)
    • roseola
    • fifth disease
  17. chicken pox (varicella zoster)
    • human herpes 3 virus, varicella zoster virus
    • herpes viridae - DNA viruses
    • capable of lysogeny (laying dorment)
    • transmission:  resp. droplets, and lesions
    • incubation: 10-20 days
    • contagious 24 hours before rash until lesions dry up
    • rash:  macules (flat pink spots) "then" papules (raised bumps) "then" vesicles (fluid filled)
    • treatment:  self limiting w/out complication, comfort
    • vaccination:  varivax; recommend for all children
  18. shingles
    • VZV activates after latency in the CNS
    • migrates down a spinal or cranial nerve to the dermatome
    • herpes zoster:  creeping rash in a belt pattern
    • zostavax:  vaccine for 60+ to reduce the risk of shingles
  19. small pox (variola)
    • cause:  smallpox (variola) virus; poxviridae (DNA viruses)
    • transmission:  resp. droplets and fomites (inanimate objects)
    • two forms:  major- highly virulent, leads to toxemia, (vascular) shock, intravascular coagulation, rash.  minor - less rash, milder illness
    • rash: macules to papules to vesicles to pustules
    • pustule:  lesions filled w/ pus (WBC, debri, bacteria, etc) odorous
    • vaccination:  developed by Edward Jenner (doctor); observed the milkmaids who had suffered from cow pox didn't contract small pox; used cowpox virus (vaccinia: vacc = cow) to protect/vaccinate people
  20. monkey pox
    • simular to small pox but milder
    • transmission:  zoonotic; from animal w/ monkey pox; come in contact w/ blood, body fluids, or rash
    • 2003 pet prairie dogs that were sick
    • can spread human to human
    • cause:  monkey pox virus; poxviridae
  21. fever blisters or cold sores
    • cause:  human herpes simplex virus type 1
    • vesicle erupts, crusts over and heals in ~ 1 week
  22. measles (rubeola) or red measles
    • cause:  measles (rubeola) virus; member paramyxoviridae; RNA virus
    • pathology:  koplik spots:  mucous membrane in mouth, red patches w/ white spots; rash (exanthema) starts at head and spreads; self limiting
    • vaccine:  part of MMR; live attenuated
  23. rubella (german measles)
    • cause:  rubivirus; togaviridae; enveloped RNA
    • transmission:  resp. droplets; transplacental transfer
    • pathology:  contagious - 2weeks before and after 3 day rash; macules (pin/red spots for 3 days); relatively mild
    • congenital rubella syndrome:  cardiac abnormalities, deafness, blindness, and mental retardation
    • vaccine:  MMR; live attenuated
  24. TORCH
    • teratogenic viruses
    • toxoplasmosis
    • other
    • rubella
    • cytomegalovirus
    • herpes
  25. teratogen
    any agent that causes congenital defects
  26. roseola
    • childhood illness
    • endemic
    • cause:  HHV6; herpesviridae; DNA
    • symptoms:  high fever, sore throat, swollen lymph nodes & a faint rash on face, neck, chest, and thighs
  27. fifth disease
    • cause:  B19 virus; parvoviridae; DNA virus
    • pathology:  low fever & malaise for 5-10 days; erythema infectiosum - red rash on cheeks and other parts of body; can be aggravated by sun and can persist for weeks
    • sequelae:  arthritic symptoms
    • pregnant:  can cause stillbirth
  28. viral skin infections with wart-like eruptions
    • warts
    • molluscum contagiosum
  29. warts
    • benign epithelial growths
    • cause:  HPV (human papilloma virus); papillomaviridae, DNA virus
  30. molluscum contagiosum
    • cause:  molluscum contagiosum virus; poxviridae; DNA virus
    • transmission:  personal direct contact, STD, formites
    • pathology:  incubation - 4 to 7 weeks; untreated can last for months; children 1-10 year old
  31. fungal infections of the skin
    • dermatophytosis
    • pathology:  tinea pedis - athletes foot; tinea capitis - head/scalp; tinea corporis - body; tinea cruris - jock itch; tinea unguium - nails
    • cause:  3 different genuses - trichophyton, epidermophyton, microsporum
    • treatment:  skin - topical antifungal; "azole"s; nails - oral, 6-12 weeks