Skin and Soft Tissue Infections Flashcards
What bacteria like to live in areas with less aciditic pH?
- S. Aureus
- S. Pyogenes
What is pictured here?

Impetigo


Describe impetigo?
- Gold crusty lesions in dermis
- Mostly in children
- Cauesed by S. Aureus
What is the treatment for Impetigo?
- Usually self-limiting
- Topical fusidic acid
- Systemic antibiotics if required
What is pictured here?

Tinea
Describe Tinea?
- Fungal infection of skin/nails
- Diagnosis made on skin scrapings
What are the most common causes of Tinea?
- Microsporum
- Trichophyton
- Epidermophyton
What is the treatment for Tinea?
- Terbinfine cream
- Terbinafine or Itraconazole systemically
- If severe or involves hair/nails

Soft tissue abscess
Describe Soft Tissue Abscesses?
- Within dermis or fat layers
- Walled-off infection and pooled pus
What is the treatment for soft tissue abscesses?
Surgical drainage

Cellulitis
Describe Cellulitis?
- Infection of dermis
- Begins in LLs then through lymphatics
- Caused by:
- S. aureus
- Beta-haemolytic streptococci
What is used to classify cellulitis?
Enron Classification
Describe the Enron Classification of Cellulitis?

Describe Streptococcal Toxic Shock?
- Toxin producing Group A Strep.
- Diffuse rash
- Primary infection in throat or skin
What is the treatment for Streptococcal Toxic Shock?
- Surgery to drain abscess
- Penicillin and Clindamycin
- Pooled human immunoglobulin in severe cases

Necrotising fasciitis
Describe Necrotising Fasciitis?
- Soft tissue infection with deep involvement
- Rapid, progressive damage
- Requires sugical debridement
What are the signs/symptoms of Necrotising Fasciitis?
- Rapid progression
- Pain out of proportion to clinical signs
- Severe systemic upset
- Visible necrotic tissue
Describe the use of imaging in Necrotising Fasciitis?
- May demonstrate fascial oedema and gas in soft tissues
- Late sign
What are the different types of necrotising fasciitis?
- Type 1 - Polymicrobial
- Type 2 - Group A Streptococcus
Describe type 1 Necrotising Fasciitis?
- Polymicrobial
- Usually complicates an existing wound
- Mix of gram positives, gram negatives and anaerobes
Describe type 2 Necrotising Fasciitis?
- Group A streptococcus
- Occurs in previously healthy tissue
- Can follow a minor injury
- S. Pyogenes only
Describe the antibiotic treatment for Necrotising Fasciitis?
- Broad spectrum therapy
- Flucloxacillin
- Benzylpenicillin
- Gentamicin
- Clindamycin
- Metronidazole
- Four black gentlemen carried money

Bite injury
What are the two major considerations in bite injuries?
- Penetrating injuries involving vulnerable structures (hands)
- Altered microbiology of wounds
Describe the treatment for bite injuries?
- 1st line antibiotic - Co-amoxiclav
- 2nd line antibiotics - Doxycycline and Metronidazole
- Surgical debridement
- Prophylaxis
- Rabies
- Tetanus

Hospital acquired infection
Describe Hospial Acquired Infections?
- At wounds and vascular access sites
- Consider MRSA infection
- Vancomycin for those colonised with MRSA
- Vascular access sites at high risk of bacteraemia
- Consider initial IV antibiotic treatment
Describe infections in people who inject drugs?
- Late presentation with neglected soft tissue infection
- S. Aureus predominates
- Offer BBV testing with admission
What is the triad in people who inject drugs?
- S. Aureus bactermia
- DVT
- Multiple pulmonary abscesses
What is PVL Staphylococcus?
- Virulence factor in some staphlococcus
- Recurrent soft tissue boils
- Transmissible
What do you do if you see this?

- Possible PVL staphlococcus
- Obtain cultures and ask lab to do PVL genotyping
What is the treatment for PVL staphylococcus?
- Surgical drainage of abscess
- Clindamycin reduce toxin production
- Decolonisation therapy to patient contacts
Decribe PVL staphylococcus decolonisation therapy?
- Topical chlorhexidine for skin/hair
- Nasal mupirocin
- Wash sheets and towels
Describe type 1 HSV?
Stomatitis cold sore

Describe type 2 HSV?
Genital herpes
How is HSV diagnosed?
Blood or vesicle fluid used for PCR
What is the treatment for HSV?
Topical/oral/IV aciclovir
What virus causes chicken pox?
Varicella zoster

Chickenpox
Describe chickenpox?
- Can be self-limiting or contagious (day 8-21 of infection)
- Childhood infection
- Congenital abnormalities if acquired during pregnancy
How is chickenpox diagnosed?
PCR of vesicle fluid
Describe the treatment of Chickenpox?
- Treat at risk adults within 48 hours of symptoms
- Immunocompromised
- Pneumonitis
- Pregnant
- Aciclovir IV

Shingles
What virus causes shingles?
Varicella zoster virus
Describe shingles?
- Reactivagtion of dormant VZV from DRG
- Dermatome distribution
- Transmissible
- Painful
Describe the treatment of Shingles?
- Treat only high-risk patients with Aciclovir
- Pain management
- NSAIDs
- Gabepentin
What should you consider in someone with Shingles infection?
HIV testing
Describe soft tissue infections that occur due to burns?
Colonisation caused by loss of protective barrier and commensal organisms
What are the 3 distinct zones of burns?
- Coagulation zone
- Stasis zone
- Hyperaemia zone
What increases the susceptibility to infections caused by burns?
Extent of burn injury
What is an important complication of paediatric thermal injuries?
Toxic shock syndrome
Name some oppurtunistic pathogens with take advantage of burns?
- Bacillus
- Enterococcus
- Pseudomonas
Describe the treatment of burn wound infections?
- Debridement of dead/infected tissue
- Antiseptics/Antimicrobials
- Tetanus prophylaxis
Which stage of Enron classification would this be?

1a
- Patient not systemically unwell and no significant co-morbidities
- Patient not yet received antibiotics or have been on antibiotics for less than 48 hours
What would be the treatment for Cellulitis class 1a?
- Patient not systemically unwell and no significant co-morbidities
- Patient not yet received antibiotics or have been on antibiotics for less than 48 hours
- Usually oral therapy for 7 days
- Treatment to cover S. aureus and S. pyogenes
- 1st line - Flucloxacillin
- 2nd line - Doxycycline
What is the treatment for stage II of Enron classification of Cellultiis?
(Patient systemically unwell or has signfiicant co-morbidities which may complicate infection
- IV therapy initially
- 1st line - Flucloxacillin
- 2nd line - Vancomycin
- Usually switched to oral after 46-72 hours
What is the treatment for stage III Enron classification of Cellulitis?
- Ambulatory care
- Daily antibiotics in ambulatory care unit
- IV Ceftriazone 2g
What is the treatment for stage IV of the Enron classification of cellulitis?
- Hospital admission for IV therapy
- Consider surgical management
- Regular clinical review
What are the complications of stage IV Enron classification of Cellulitis?
- Local
- Severe tissue destruction
- Distant
- Septic shock
Name some conditions which can mimic cellulitis?
- Bites
- Hospital acquired infections
- Infections in people who inject drugs
- PVL Staphylococcus aureus