chapter 4 microbial diseases of the skin
DESCRIPTION
Chapter 4 MICROBIAL DISEASES OF THE SKIN. Miss Rashidah Hj Iberahim. Content. Bacterial skin diseases* Viral skin diseases Fungal skin diseases Wound infection – gas-gangrene*. Bacterial infections. Gram positive infections. Staphylococcus sp. Streptococcus sp. - PowerPoint PPT PresentationTRANSCRIPT
CHAPTER 4MICROBIAL DISEASES OF THE SKIN
Miss Rashidah Hj Iberahim
Content
Bacterial skin diseases* Viral skin diseases Fungal skin diseases Wound infection – gas-gangrene*
Bacterial infections
Gram positive infections
Folliculitis and other skin lesions
Scalded skin syndrome
Scarlet Fever Erysipelas
Staphylococcus sp Streptococcus sp
Folliculitis(pimples / pustules)
• 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
Pathogenesis Transmission
on base of eye lashes – sty
A larger and deeper form – abscess
Exterior abscess – furuncle / boil
Massive lesion - curbuncle
Scalded Skin Syndrome
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
1. 1st stage – redness of surrounding area
2. 2nd stage – 1-2 days large, soft and easily ruptured vesicles around the body
3. 3rd stage – the lesion getting dry and scale
Pathogenesis Symptoms
Peeling off skin
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
Rash
The best medicine is Penicillin – decrease mortality rate
Erysipelas
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)
Pathogenesis
Viral Diseases
Rubella
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
The disease Transmission
Rubella
Immunity assessment on pregnant woman
Rubella – specific IgM antibody
Other variety serology test
Currently using rubella vaccine (MMR)
Diagnosis Prevention
Measles/ Rubeola
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 Subacute sclerosing
panencephalitis (SSPE)
Diagnose by its symptoms
2nd accompanied by bacterial infection
Using the same vaccine as rubella and mumps (MMR)
Diagnosis and prevention
Chicken pox and Shingles
1 virus – 2 diseases CP – varicella, S –
zoster (varicella-zoster virus)
2nd inf by 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
The disease Symptoms
Disease progression
1. Virus enter upper respiratory tract/ conjuctiva – replicates
2. Carried by blood to various tissues – replicates
3. Release of viruses causes fever and malaise
4. After 14 – 16 days, present of small, irregular, rose-coloured skin lesions
5. Fluid become cloudy, dry and crust over 2-4 days (virus cycle)
6. Rashes start from scalp and trunk, face and limbs, to mouth/throat/ vagina, and may spread to resp tract and GIT
Chicken pox and shingles
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)
Transmission Diagnosis and treatment
Gas gangrene
Wound infection
Gas Gangrene
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
Pathogenesis Symptoms
Photograph before right leg amputation (hemipelvectomy) of a patient with gas gangrene. The right thigh is swollen, edematous and discoloured with necrotic bullae(large blisters). An impressive crepitation is already palpable. At this juncture, the patient is in shock.
Others diseases
1. Wart
Caused by Human Pappiloma Virus (DNA)
Plane wart Plantar wart Face , back of hands sole
Genital wart
Condylomata accuminata
Penile, vulvar skin, perianal area
Sexual partner Child---sexual abuse Some: oncogenic:16, 18
2. Molluscum contagiosum Pox virus Child Face, neck Central punctum Hunderson-patterson bodies
Superficial mycosisDeep mycosis
Fungal
Dermatophyte infection
Skin Hair Nails
Tinea pedisAdult (athlete’s)Toe webs , instepT.rubrum, T.mentagrophytes
Tinea ungum
T.rubrum, T.mentagrophytes
Tinea corporis:
TrunkActive edgeT.rubrum
T.cruris
T.manun
Tinea capitis
Well circumscriped pruritic scaling area of hair loss
Black dot (T.tonsurans) Gray patch (M.audouinii), Kerion (T.verrucosum) Favus (T.schoenleinii)