Skin and Soft Tissue Infections Flashcards
List 6 types of infections commonly caused by water exposure.
Aeromonas Edwardsiella tarda Erysipelothrix rhusiopathiae Vibrio vulnificus Mycobacterium marinarum Vibrio parahaemolyticus
Define cellulitis.
Infection of the deeper dermis and fat layers after bacteria breach the skin barrier
What are the most common causes of cellulitis? (2)
Staph. aureus
Beta haemolytic streptococci, e.g.
-Strep. pyogenes
Describe the clinical features of cellulitis. (5)
What is the cellulitis triad? (3)
CELLULITIS TRIAD:
Oedema
Erythema
Warmth
OTHER FEATURES:
Skin changes
Fever
List 6 differential diagnoses for cellulitis.
Stasis dermatitis Acute arthritis Pyoderma gangrenosum Hypersensitivity/drug reactions DVT Necrotising fasciitis
List 4 general risk factors for cellulitis.
List 8 local risk factors for cellulitis.
GENERAL RISK FACTORS: Venous insufficiency Lymphoedema Pregnancy White Caucasian
LOCAL RISK FACTORS: Ulcers Eczema Athlete's foot Burns Surgical wounds IVDUs Trauma Tattoos
Describe the classification of cellulitis.
HINT: there are 4 classes.
CLASS 1:
No sepsis
No co-morbidities
CLASS 2: Possible systemic illness At least one of: -Peripheral vascular disease -Obesity -Venous insufficiency
CLASS 3:
Significant systemic illness
Unstable co-morbidities
CLASS 4:
Sepsis
Necrotising fasciitis
Unstable co-morbidities
In cellulitis, what can cause failure to respond to antibiotics? (3)
Resistant organisms (e.g. MRSA) Underlying conditions (e.g. bone infection, abscess) Incorrect diagnosis
When would you consider hospital admission in cellulitis patients? (4)
Severe, localised pain
Rapidly evolving skin lesions
SIRS:
- HR 100+
- RR 20+
- Temp <36 or 38+
- WCC <4 or 12+
Sepsis:
- SIRS
- Organ dysfunction (confusion, hypotension or RR 22+)
How would you treat cellulitis? Consider:
a) Mild cellulitis
b) Moderate cellulitis
c) Severe cellulitis
MILD CELLULITIS:
Flucloxacillin (oral)
-Duration: 7 days
MODERATE CELLULITIS:
Flucloxacillin (oral)
-Duration: 10 days
SEVERE CELLULITIS: Flucloxacillin (IV) Gentamicin (IV) Clindamycin (IV) -Duration: 10 days
Define erysipelas.
Infection of the upper dermis and superficial lymphatics in the skin
Define impetigo.
Superficial bacterial infection of the skin
Define necrotising fasciitis.
Severe inflammation and infection of the muscle sheath that leads to necrosis of the subcutaneous tissue and adjacent fascia
Define tinea.
A superficial dermatophyte infection of the epidermis, characterised by scaly, inflammatory or non-inflammatory patches
Define dermatophyte.
A pathogenic fungus that grows on skin, mucous membranes, hair, nails and other body surfaces
What are 2 other names for erythema infectiosum?
Define this disease.
Fifth disease, slapped cheek syndrome
A common, benign infection in children, caused by human parvovirus B19
What is erysipelas caused by?
Group A streptococci (strep. pyogenes)
Describe the clinical features of erysipelas.
Raised lesion
Clear line of demarcation
Elevated ASOT (antistreptococcal antibody titres)
Distribution:
- Butterfly distribution in face (20%)
- May involve the ear (cellulitis does not)
- Legs (80%)
How would you treat erysipelas?
Flucloxacillin or amoxicillin
PLUS
Gentamicin
What is impetigo caused by? (4)
Primary infection:
- Staph. aureus
- Other staphylococci
- Streptococci
Secondary infection:
-Herpes simplex virus
Describe the initial features of necrotising fasciitis. (5)
Describe the later features of necrotising fasciitis.
INITIAL FEATURES: Severe and out of proportion pain Rapid spread Systemically unwell patient Erythema and swelling No well-defined margins
LATER FEATURES: Colour change: red/purple to blue/grey Bullae development Anaesthesia Dusky skin Necrosis Skin crepitus Complete tissue destruction
Which 5 antibiotics would you give for necrotising fasciitis?
Flucloxacillin IV Benzylpenicillin IV Gentamicin IV Clindamycin IV Metronidazole IV
What organism most commonly infects animal bites?
Pasteurella
Which organisms can cause tinea? (3)
Which is the most common?
Most common: trichophyton
Other causes:
- Microsporum
- Epidermophyton
What causes erythema infectiosum?
Human parvovirus B19
What causes hand, foot and mouth disease?
Coxsackie virus A16
What is scalded skin syndrome also called?
What causes it?
Ritter’s disease; pemphigus neonatorum
Staph. aureus
