Chapter 4 MICROBIAL DISEASES OF THE SKIN

1. Chapter 4MICROBIAL DISEASES OF THE SKIN Miss RashidahHjIberahim

2. Content • Bacterial skin diseases* • Viral skin diseases • Fungal skin diseases • Wound infection – gas-gangrene*

3. Bacterial infections

4. Gram positive infections Staphylococcus sp Streptococcus sp • Folliculitis and other skin lesions • Scalded skin syndrome • Scarlet Fever • Erysipelas

5. Folliculitis(pimples / pustules) Pathogenesis Transmission • S. aureus colonize skin and upper resp. tract of infants within 24 hrs after birth • Invade thru hair follicle- producing folliculitis (form of pimples and pustules) • Encapsulated of abcess- x shedding n antibiotic reach the area • Treatment-surgery • Spread thru hosp personnel, asympt carrier n hosp visitors/catheters and splinters for older patient /nasal droplets and fomites • 100 m/org were enough to cause infection in suture

6. on base of eye lashes – sty

7. A larger and deeper form – abscess

8. Exterior abscess – furuncle / boil

9. Massive lesion - curbuncle

10. Scalded Skin Syndrome Pathogenesis Symptoms • By certain exotoxin-producing strain of S.aureus (2 types exfoliatins) • Common in infant; adult (toxic shock syndrome) • Exotoxin move thru veins to the skin causing outer layer peeling off in leaflike sheets • Can lead to septicemia and very antigenic • Can cause reinfection – antibiotic very important • 1st stage – redness of surrounding area • 2nd stage – 1-2 days large, soft and easily ruptured vesicles around the body • 3rd stage – the lesion getting dry and scale

11. Peeling off skin

12. Scarlet Fever Pathogenesis • Also known as scarlatina • By Streptococcus pyogenes • Contain 3 types of erythrogenic toxin – reddening • The strain was 1st infected by temperate phage – erythrogenic toxin that leads to rash • Only infecting new exposure pt • low- virulent strain – glomerulonephritis / rheumatic fever • Reinfection that already defends by previous antibiotic – leads to strep throat (but carrier of scarlet fever) • Might also caused by fomites

13. Rash • The best medicine is Penicillin – decrease mortality rate

14. Erysipelas Pathogenesis • Face- small, bright, raised, rubbery lesion. • Beta hemolytic gp A Strept. • Always occur after pt having surgery or wounds • Producing hyaluronidase enzyme and toxin • Minor abrasion— • sup. Lymph vessels (causing septicemia, abscess,pneumonia, endocarditis, arthritis, death)

15. Viral Diseases

16. Rubella The disease Transmission • Rashes appear on trunk after 16-21 days after infection • Caused by togavirus • 2ndary: arthritis and arthralgia • Can caused congenital rubella syndrome • Mainly through nasal secresion • Direct contact among children age 5 – 14 • Infected infants expose to hospital personnel

17. Rubella Diagnosis Prevention • Immunity assessment on pregnant woman • Rubella – specific IgM antibody • Other variety serology test • Currently using rubella vaccine (MMR)

18. Measles/ Rubeola Diagnosis and prevention • Caused by Rubeola virus • Koplik’s spots – bluish specks in upper lips and cheek mucosa • Rubella – pink n flat rash • Rubeola – red and raised • Other complications : • Measles encephalitis • Subacutesclerosingpanencephalitis (SSPE) • Diagnose by its symptoms • 2nd accompanied by bacterial infection • Using the same vaccine as rubella and mumps (MMR)

19. Chicken pox and Shingles The disease Symptoms • 1 virus – 2 diseases • CP – varicella, S – zoster (varicella-zoster virus) • 2ndinfby S. aureus • In children • Damages in blood and lymphatic drainage • During latent period, stay in ganglia of nerve cells • CP = Causing blood clot and hemorrhage, Cause death • S = pain, burning, prickling of the skin when it reactivate

20. Disease progression • Virus enter upper respiratory tract/ conjuctiva – replicates • Carried by blood to various tissues – replicates • Release of viruses causes fever and malaise • After 14 – 16 days, present of small, irregular, rose-coloured skin lesions • Fluid become cloudy, dry and crust over 2-4 days (virus cycle) • Rashes start from scalp and trunk, face and limbs, to mouth/throat/ vagina, and may spread to resp tract and GIT

21. Chicken pox and shingles Transmission Diagnosis and treatment • CP – Infect between 5-9 yrs old • V – age >45 yrs old • Spread by respiratory secretion and fluid from moist lesion (not the dry lesion) • Using rapid laboratory test • Treatment – antiviral agent (valtrex and neurontin)

22. Wound infection Gas gangrene

23. Gas Gangrene Pathogenesis Symptoms • Caused by more than 1 bacteria = Clostridium sp. • Spores of the bacteria expose during injuries and surgery • The symptoms getting severe because of toxin and enzyme production • Suddent onset = 12-48 hrs after exposure • Foul odour • Ferment muscle carbohydrates • “snap, crackle and pop” • High fever, shock, massive tissue destruction, blackening of tissues

24. Photograph before right leg amputation (hemipelvectomy) of a patient with gas gangrene. The right thigh is swollen, edematous and discoloured with necroticbullae(large blisters). An impressive crepitation is already palpable. At this juncture, the patient is in shock.

25. Others diseases

26. 1. Wart Caused by Human Pappiloma Virus (DNA)

27. Plane wart Plantar wart Face , back of hands sole

28. Genital wart • Condylomataaccuminata • Penile, vulvar skin, perianal area • Sexual partner • Child---sexual abuse • Some: oncogenic:16, 18

29. 2. Molluscum contagiosum • Pox virus • Child • Face, neck • Central punctum • Hunderson-patterson bodies

30. Fungal Superficial mycosis Deep mycosis

32. Dermatophyte infection • Skin • Hair • Nails

33. Tineapedis Adult (athlete’s) Toe webs , instep T.rubrum, T.mentagrophytes

35. TineaungumT.rubrum, T.mentagrophytes

36. Tineacorporis: Trunk Active edge T.rubrum

37. T.cruris

38. T.manun

39. Tineacapitis Well circumscriped pruritic scaling area of hair loss • Black dot (T.tonsurans) • Gray patch (M.audouinii), • Kerion (T.verrucosum) • Favus (T.schoenleinii)