2. Skin, Soft Tissue, and Wound Infections Flashcards
Cause of swimmer’s itch?
Parasitic skin infection by cercariae (burrows into skin)
Source of M. ulcerans
Tropical wetlands (swamps)
Necrotizing fasciitis agents
- S. pyogenes
- S. aureus
- Anaerobes
Pyoderma that may be caused by Aeromonas (fresh water) or Vibrio (sea water)
Cellulitis
Begin as painless papules which become hemorrhagic vesicles that may become necrotic
Anthrax
Causes syphilis
Treponema pallidum
5 uncommon bacterial infections of the skin
- Mycetoma
- Chromoblastomycosis
- Phaeohyphomycosis
- Mucormycosis
- Lobomycosis
Skin infection due to HSV I? HSV II?
I - cold sores
II - genital herpes
Osler nodes and Janeway lesions are indicative of …?
Endocarditis
Fungal media should be added to all ________ specimens
burn
Erythrasma
- Brown, scaly skin patches
- Groin, inner thighs, armpits, toe webs
- Usually in men, obese, diabetics
Corynebacterium minutissimum
Pyoderma common caused by Grp A strep; S. aureus more rare
Erysipelas
usually a progression of untreated impetigo
infection penetrates the dermis; painful sores at first, then deeper ulcers form
ecthyma
Tinea versicolour
Diffuse distribution of hypopigmented macules
Malassezia furfur (yeast)
Intertrigo
Infectious dermatitis common in skin folds of infants and obese adults
Candida albicans
2 infections in which Wood’s lamp is useful
Erythrasma - lesions fluoresce coral red
Dermatophyte infections - Microsporum fluoresces yellow-green
The only organisms that can grow using keratin
dermatophyte fungi
Treatment for this infection could be local hyperthermia (42-43 degC)
Sporotrichosis
“Swimming pool granuloma”
Mycobacterium marinum
Itraconazole (1st line drug) is for what infection?
Sporotrichosis
Pyoderma caused by Erysipelothrix rhusiopathiae
Erysipeloid
TSI is often used to screen for this infection (causes H2S+)
Erysipeloid
Difference between TSS and scalded skin syndrome effect on skin layers?
TSS = necrosis of FULL epidermal layer
SSS = only top layers shed
German measles AKA ______ is caused by ________
rubella
Rubivirus
Viral infection that is caused by HPV
Warts
2 animal bite related organisms that show the same plate growth and only differ in 1 chemical test.
Which 2 organisms and which test?
Pasteurella multocida, Bergeyella zoohelcum
Urea (P. multocida is NEG)
Myonecrosis agents
AKA gas gangrene when caused by C. perfringens, other Clostridium
Also:
Anaerobic strrep, Enterobacteriaceae
Sulphur granules discharge is common in this infection
Actinomycosis
Causative agent in non-bullous impetigo? Bullous imepetigo?
Non-bullous - Grp A strep
Bullous - S. aureus
English measles AKA __________ is caused by ________
rubeola
Morbillivirus
Treatment for uncommon bacterial skin infections?
Surgical debridement
Small painful nodules on pads of fingers and toes due to immune complexes deposited in soft tissue
Osler nodes
How to differentiate S. intermedius from S. aureus?
S. intermedius is PYR+
4 types of infectious dermatitis
Intertrigo
Erythrasma
Dermatophytosis
Tinea versicolour
Myositis agents
S. aureus, almost anything
Uncommon bacterial skin infection that possibly involves bone
Mycetoma
Toxin that causes scarlet fever? Causative agent?
Erythrogenic toxin. GAS.
Acid-fast stains and culture are required for these infections
Mycobacterial infections
Skin manifestation caused by S. aureus exfoliative toxins (pyrogenic)
Scalded skin syndrome
Transmitted by body lice (organism + infection)
Bartonella quintana
Trench fever
Term used to denote a dermatophyte infection
tinea
Infection of nail cuticle
Paronychia
Special media set up for this type of infection includes: PDA, Mycosel, IMA, SAB, 10% KOH direct exam
Dermatophyte
Impetigo
- Itchy - scratching spreads it
- Disease of childhood
Schools, daycares (crowded conditions)
GAS (non-bullous)
S. aureus (bullous)
Borrelia burgdoferi
Lyme disease
bull’s eye lesion
Small hemorrhagic spots that don’t blanch; usually caused by bacterial infections
Petechiae
Bartonella henselae culture requirements and s/?
CHOC, BAP high humidity and CO2 helpful
gnb, occasionally curved
- Tricophyton
- Microsporum
- Epidermophyton
can all cause?
Dermatophytosis
SXT (choice) also Imipenem, amikacin may be used to treat?
Nocardiosis
2 Mycobacterium where the source can be soil
M. foruitum
M. chelonae
Animal bite related, long fusiform gnb that exhibits gliding motility
Capnocytophaga canimorsus
Painless hemorrhagic macules on palms and soles
Janeway lesions
Specimens required for dermatophyte infection?
Dry skin scraping
Hair or nail clippings
Purpose of KOH in wet prep direct microscope examination of skin scrapings
Clears tissues => easier to see fungal elements
Specimens collected for Bartonella henselae infection?
Lesion biopsies, blood cultures
Ecthyma gangrenosum (EG) is associated with what bacteria?
Pseudomonas
Also S. aureus, Candida
Antifungal amphotericin B is used to treat..?
Mucormycosis
Streptobacullus moniliformis is the causative agent of?
Rat bites