Skin and soft tissue infections Flashcards
(22 cards)
What is cellulitis?
Cellulitis is an acute spreading infection of the skin with visually indistinct borders that principally involves the dermis and subcutaneous tissue.
What organisms commonly cause cellulitis?
B haemolytic strep (group A) and staph aureus
What are Sx of cellulitis?
- Erythema
- Dull pain or tenderness
- Warmth
- Blistering
- Erosions and ulceration
- Swelling/oedema
May be systemic symptoms if severe
What are risk factors for cellulitis?
- Previous episode(s) of cellulitis
- Venous disease (e.g. gravitational eczema, leg ulceration and/or lymphoedema)
- Current or prior injury (e.g. trauma/surgical wounds)
- Immunodeficiency
- Diabetes
- Chronic kidney disease
- Chronic liver disease
- Obesity
- Pregnancy
What Ix in cellulitis?
None normally needed.
Can do routine bloods (WCC/CRP), cultures, and skin swabs if systemically unwell
What is Rx of cellulitis?
• Analgesia e.g. paracetamol, ibuprofen
• Ensure adequate oral intake or IV fluids if required
• Marking the edge of erythema to monitor spread/regression
Antibiotics e.g. flucloxacillin (or doxy) 7 days oral, IV if unwell
What is erysipelas?
Erysipelas is a distinct form of superficial cellulitis with notable lymphatic involvement. It is raised and sharply demarcated from uninvolved skin.
usually affects face
What is impetigo?
Impetigo is a superficial bacterial skin infection which is highly contagious and common in children
What are Sx of impetigo?
• Golden encrusted skin lesions with inflammation localised to the dermis, giving erythematous base.
• Often well-defined localised lesions
Occur on nose and face
What are causes of impetigo?
Staph aureus and group A strep
What is Rx of cellulitis?
• Topical ○ Fusidic acid ○ Given in localised infections • Oral antibiotics ○ Flucloxacillin ○ Given for 7 days if severe.
What is tinea?
A superficial fungal skin infection which invades and grows in dead keratin of the skin and nails.
What Ix for tinea?
Clinical diagnosis, but can do skin scrapings and scalp brushing
What Rx for tinea?
Topical anti-fungal e.g. terbanifine, ketonacazle shampoo, systemic terbanifine in more severe infections
What is a soft tissue abscess?
Infection within the dermis or fat layers with the development of walled off infection and pooled pus.
How is soft tissue abscess treated?
• Lysing and surgical drainage
○ There is limited antibiotics penetration into the abscess
○ Antibiotics shouldn’t be required if abscess is fully drained and there is no surrounding cellulitis.
• PVL toxin; virulence factor for causing boils and abscesses, necrotising infections. May change antibiotics choice. Clindamycin stop production of toxin
What is necrotising fasciitis?
A rapidly progressive infection of the deep fascia causing necrosis of the subcutaneous tissue.
What are the 2 types of NF?
type 1 = polymicrobial. Older people, existing wounds, scrotal
type 2 = monomicrobial, usually strep pyogenes, in younger people with healthy tissue after a cut
What are risk factors for NF?
- Recent wound or bite, or surgery
- Diabetes
- Immuno-compromised individuals
- Alcohol XS
- IVDU
- Chronic kidney disease
- NSAIDS
What Ix for NF?
Treat immediately/call surgeons if suspected.
Can do bloods, blood cultures, gram stain of exudate
MRI scan can show extent of NF, but can delay treatment
What Rx for NF?
Surgical debridement
Antibiotics: benzypenicillin + flucloxacillin + gentamicin + clindamycin + metrondiazole
IVIG if type 2 NF caused by group A strep may help
What are Sx of NF?
Pain out or proportion to symptoms
Erythema, painless ulcers, black necrotic skin, crepitus if over a joint
Systemic Sx e.g. fever, hypotension, tachycardia
