Bacterial Skin and Soft Tissue Infections Flashcards
What is the definition of cellulitis?
Cellulitis is an infection of the deep dermis and subcutaneous tissue
What are the risk factors for cellulitis?
Diabetes Venous insufficiency Chronic oedema / lymphoedema Eczema Obesity Toe web abnormalities
What associated skin changes can occur in cellulitis?
Peu d/orange
Dermal necrosis
Blistering
Superficial bleeding
What constitutional symptoms can occur in cellulitis?
Fever
Malaise
Lymphadenopathy / lymphangitis
Hypotension / tachycardia
When is a skin swab required in the investigation of cellulitis?
When an atypical organism is suspected
When should a patient with cellulitis be admitted to hospital?
They are elderly They are immunosuppressed They have significant co-morbidites They have systemic symptoms There is suspicion of atypical organism
What are the potential complications of cellulitis?
Sepsis
Chronic oedema
What is the management of cellulitis?
Empirical antibiotics (fluxcloxacillin, vancomycin) Supportive care - analgesia, VTE prophylaxis, fluid management, wound care
What are the risk factors for necrotising fascitis?
Recent surgery Cutaneous trauma Hospitalisation IVDU Immunosupression Ulcerative conditions
Describe the different subtypes of necrotising fascitis?
Type 1 - polymicrobial infection usually with Ana anaerobe and a facultative anaerobe
Type 2 - mono microbial infection, commonly group a strep
Type 3 - mono microbial infection, usually a gram negative bacteria
Type 4 - moonomicrobial infection with fungus usually in immunocompromised patients
Describe the appearance of necrotising fascitis?
Severe, disproportionate pain -> anaesthesia over infection site
Oedema and erythema
Associated skin changes - Crepitus, vesicles, bullae, grey discolouration
Systemic signs of infection
What is the most common causative organism of erysipelas?
Strep pyogenes
What antibiotics are typically used in the treatment of erysipelas?
Penicillins
Clindamycin
Erythromycin
What is the definition of impetigo?
A common superficial, highly contagious, blistering bacterial infection of the skin
What areas of the skin are typically affected by bullous impetigo?
Skin folds - axillae, groin etc.
What groups of patients typically develop bullous impetigo?
Newborn babies
Immunocompromised adults
What are the most common causative organisms of impetigo?
Group A strep Staph aureus (s.aureus is the cause of bullous impetigo)
What more serious condition can bullous impetigo evolve into?
Staphylococcal scalded skin syndrome
What is the management of impetigo?
Usually no treatment as it will usually self-resolve
In some cases topical antibiotics are used and if severe or refractory oral antibiotics are used
Good skin hygiene is important
What is staphylococcal scalded skin syndrome?
A blistering skin infection caused by s.aureus
What is pathophysiology of staphylococcal scalded skin syndrome?
epidermylotic exotoxin A and B are released by staph aureus and cause detachment within the epidermal layer due to the breakdown of desmosomes
Describe the presentation of staphylococcal scalded skin syndrome?
Fever, irritability and widespread erythema
Within 12-48 hours widespread fluid-filled blisters forms on face, buttocks and intertriginous areas (but NOT mucosa) and these are easily breakable
Nikolsky’s sign is positive
What is the most common infectious cause of folliculitis?
S.aureus
Describe the appearance of folliculitis?
Multiple erythematous folliculocentric papules and pustules.
Often puritic.
Painful furnaces develop if the infection spreads more deeply.
Often resolves with hyperpigmentation in darker skin types
