Skin and soft tissue Infections Flashcards
What makes up the normal flora of the skin?
Coagulase-negative staphylococci
Staph aureus
What are the signs and symptoms of herpes simplex generally?
cold sores - come and go by triggers e.g. infection/stress
tingling
What are the two stages of herpes simplex? What are their features?
Primary: occurs once, rara, extensive, painful lesions, inside mouth
Secondary: Happens more than once, Peri-oral, weeping, vesicular
How is herpes simplex diagnosed?
Clinical
Vesicle fluid - PCR
What is the treatment for cold sores? (How it is given is important here?
Topical acyclovir
What is the treatment for genital herpes? (How it is given is important here?
Oral acyclovir
What is the primary and secondary manifestation of varicella zoster virus?
Primary: chickenpox
Secondary: shingles
What is latent varicella zoster virus triggered by?
Physical/emotional insult
Tingling/pain
How does varicella zoster virus present?
Weeping vesicular rash
Dermatomal distribution - diagnostic
How is varicella zoster virus diagnosed?
Clinical
Vesicle fluid - PCR
What is the treatment for varicella zoster virus?
Oral/IV acyclovir - depending on severity
What does Molluscum contagiosum virus look like?
Raised, pearly lesions
Umbilicated - central depression
How is Molluscum contagiosum diagnoised?
Clinically
What is the treatment for Molluscum contagiosum?
None - disappears itself
Name 6 bacterial infections of the skin
Impetigo Erysipelas Cellulitis Necrotising fasciitis Gas gangrene Anthrax
Impetigo is infection of which layer of the skin?
Epidermis
What pathogen normally causes impetigo?
S.aureus
S.pyogenes
Both
What does impetigo present as?
Plaque like lesions
Yellowish exudate
Thick scabs - ‘honey crusted’
How is impetigo diagnosed?
Clinically
Bacterial cultures - useful for sensitivity testing
Erysipelas is infection of which layer of the skin?
Dermis
What pathogen normally causes erysipelas?
S.pyogenes
How does erysipelas present?
Pain Tenderness Fever/malaise Well demarcated inflammatory lesion - red, swollen, hot Lymph node enlargement
How is erysipelas diagnosed?
Clinical diagnosis
Cellulitis is infection of which layer of the skin?
Skin and subcutaneous tissue
What pathogen normally causes cellulitis?
S.aureus
S.pyogenes
How does cellulitis present?
Fever/malaise
Diffuse inflamed lesion - Erythema, swelling, tenderness, heat
Margins unclear
How is cellulitis diagnosed?
Clinically
Lesion swabs if possible
Not cellulitis if bilateral!
Anthrax is caused by which pathogen?
Bacillus anthracis
Where is anthrax acquired from?
Imported wool, hair and animal hinds
Necrotising fasciitis is infection of which layers of the skin?
Skin and subcutaneous tissues
What two types of factors cause necrotizing fasciitis?
Type 1: Polymicrobial - enteric gram -ve bacilli, anaerobes
Type 2: Streptococcus pyogenes
How does necrotizing fasciitis present?
Fever/malaise Dark Rapidly spreading Necrotising lesion Blisters
How is necrotizing fasciitis diagnoised?
Microscopy and culture of:
Debraided material
Blood
What is the treatment for necrotizing fasciitis?
IV antibiotics
Surgical debridement - removal of dead tissue
What type of pathogen causes gas gangrene?
anaerobic bacteria
How does gas gangrene present?
Same as necrotizing fasciitis
Feels soft/squishy like there is gas inside
When does gas gangrene tend to occur?
Areas of poor blood supply
i.e. amputees that have PVD
How is gas gangrene treated?
IV antibiotics
Surgical debridement
What is the empirical therapy used for infections caused my staph aureus or strep pyogenes?
Flucloxicillin
What is the empirical therapy used for necrotizing fascitis?
Meropenem
Clindamycin
What fungi causes dermatophyte infections?
Tricophyton spp
Microsprum spp
Name 3 dermatophyte skin infections
Tinea corporis
Tinea pedis (athlets foot)
Tinea cruris
Name a dermatophyte nail infection
Onychomycosis
Name a dermatophyte scalp infection
Tinea capitis (scalp ringworm)
How are dermatophyte infection diagnosed?
Skin scrapings
Microscopy and culture
What are the topical antifungal treatments used for dermatophyte skin infection?
Clotrimazole
Terbinafine
What are the oral antifungal treatments used for dermatophyte scalp and nail infection?
Terbinafine
Itraconozole
What antibiotics are used to treat impetigo?
Fusidic acid
Mupirocin
