29. Skin and Soft Tissue Infections Flashcards
What pathogens cause cellulitis?
Staph aureus
Strep pyogenes
Less commonly C or G B haemolytic strep
What are the risk factors for cellulitis?
Previous cellulitis Diabetes Obesity Peripheral vascular disease Lymphoedema Skin breaks
What are the clinical features of cellulitis?
Erythema Pain Swelling Hot to touch Patient may be systemically unwell
What samples should be taken from a patient with cellulitis?
Blood cultures
Skin swabs
How should cellulitis be managed?
Mark boundaries
Empiric flucloxacillin
What directed treatment should be given if cellulitis is caused by strep pyogenes?
Benzylpenicillin
What is necrotising fasciitis?
Destruction of skin, subcutaneous and peri-muscular fat by liquefactive necrosis
What are the types of necrotising fasciitis?
Polymicrobial
Group A beta haemolytic strep
Gas gangrene
How does a patient with necrotising fasciitis present?
Pain is out of proportion to their wound
Very systemically unwell
How should necrotising fasciitis be managed?
Urgent surgery for debridement
Tissue for culture
Blood cultures
What is the empiric treatment for necrotising fasciitis?
Vancomycin
Piperacillin-tazobactam
Clindamycin
What is Fournier’s Gangrene?
Necrotising fasciitis in the perineum
Can involve scrotum, penis and abdominal wall
What is gas gangrene?
Necrotising myositis
What pathogen causes gas gangrene?
Toxin-producing clostridia
What is the link between colon cancer and gas gangrene?
C. septum from the GIT can spread haematologically
What are the clinical features of gas gangrene?
Acute onset of severe pain
Fluid or gas filled blisters on skin
Foul odour and crepitus
How is gas gangrene diagnosed?
Gas seen in tissues on X-ray
Wound swab, blister fluid or tissue for culture
Blood cultures
What is the treatment for gas gangrene?
Debridement
Empiric: benzylpenicillin for clostridia
Hyperbaric oxygen
What pathogens cause impetigo?
Staph aureus
Group A strep
Impetigo is highly contagious. T/F?
True
What antibiotic treatment is used for impetigo?
Flucloxacillin
What pathogen causes folliculitis?
Staph aureus
What pathogens cause abscesses?
Staph aureus or polymicrobial
What is the treatment for abscesses and furuncles?
Drain
What is the difference between a carbuncle and a furuncle?
Carbuncles are larger and deeper
Where are carbuncles found?
Nape of neck
Back
Thighs
What is erysipelas?
Cellulitis with lymphatic involvement
Who is more likely to get erysipelas?
Diabetics
Extremes of age
What pathogens cause erysipelas?
Group A strep
What is the treatment for erysipelas?
Benzylpenicillin
What skin infection is associated with Nikolsky’s sign?
Scalded skin syndrome
What pathogen causes scalded skin syndrome?
Staph aureus
What symptoms are associated with scalded skin syndrome?
Fever
Hypotension
Skin tenderness
The highest mortality of scalded skin syndrome is in neonates. T/F?
False
Highest mortality in adults
What antibiotic is used to treat scalded skin syndrome?
Flucloxacillin
What causes acne?
Excess sebaceous secretion by follicles and infection by propionobacteria
What pathogens are involved in infections of human and animal bites?
Mouth flora
Staph
Strep
What treatment should be given after a human/animal bite?
Swabs for culture and susceptibility
Tetanus prophylaxis
Co-amoxiclav
What diabetic foot infections are non-limb threatening?
Cellulitis without abscess or vascular compromise
What diabetic foot infections are limb threatening?
Vascular compromise
Abscess
Osteomyelitis
Gangrene
What is the empiric treatment for limb-threatening diabetic foot infections?
Piperacillin-tazobactam
What is the empiric treatment for non-limb threatening diabetic foot infections?
Flucloxacillin or co-amoxiclav
What is the difference between clean, clean-contaminated and contaminated surgeries?
Clean: no breech of tract
Clean-contaminated: planned surgery that breeches tract
Contaminated: emergency due to rupture
What are the classifications of SSIs?
Superficial, deep, organ
What pathogens are involved in SSIs?
Staph aureus B-haemolytic strep Gram - bacilli Anaerobes Coagulase negative staph on prosthetic materials
How are SSIs prevented?
Optimise risk factors of patient
De-colonisation of MRSA carries
During: aseptic technique
After: remove drains, asepsis when caring for wound
What pathogen causes warts?
HPV
How are warts treated?
Excision, salicylate and lactic acid ointment
Cryotherapy
What pathogen causes hand, foot and mouth disease?
Coxsackie A virus
What treatment is needed for Coxsackie A virus?
None: self-limiting
What are causes of candidiasis?
Antibiotics
Steroids
Pregnancy
Immunosuppression
How is candidiasis treated?
Topical clotrimazole
Oral fluconazole
Tinea is not infectious. T/F?
False, it can be gotten from other people or animals
What is the treatment for tinea pedis/corporis?
Topical terbinafide
Oral terbinafide or itraconazole
What is the treatment for tinea capitis?
Oral terbinafide or itraconazole
Ketoconazole shampoo
Where does a pityriasis versicolor rash usually appear?
Chest and back
What is the treatment for pityriasis versicolor?
Topical ketoconazole shampoo
How does scabies present?
Mite burrows into finger webs
Very itchy especially at night
What is the treatment for scabies?
Topical permethrin
Wash clothes and bedsheets
What is the treatment for lice?
Malathion or permethrin
Fine combing
Bathing/washing clothes