Skin and Soft Tissue Infections 1 Flashcards
What is Impetigo
- Superficial, highly infectious, skin infection
- Common in young children (hands, face and neck)
- Golden crust is highly suggestive of this diagnosis
Most common cause of Impetigo
Staph aureus
Predisposing factors for Impetigo
- Minor trauma
- Burns
- Poor hygiene
- Insect bites
- Chickenpox, eczema, atopic dermatitis
Treatment for Impetigo
- Small areas = topical antibiotics
- Large areas = topical antibiotics + oral antibiotics e.g. Flucloxacillin
What is Erysipelas
- Infection of upper dermis (most common in lower limbs)
- Painful red area (no central clearing)
- Associated fever
- Regional lymphadenopathy
- Typically has distinct elevated borders
Most common cause of Erysipelas
Strep Pyogenes
What is cellulitis
- Diffuse skin infection involving deep dermis and subcutaneous fat
- Presents as a spreading erythematous area with no distinct borders
- Fever and local lymphadenopathy is common
Most likely cause of cellulitis
Staph aureus and Strep pyogenes
Predisposing factors for cellulitis
- Diabetes mellitus
- Tinea pedis (athlete’s foot)
- Lymphoedema
Treatment for cellulitis and erysipelas
- Anti-staphylococcal and anti-streptococcal antibiotics
- In extensive disease = IV antibiotics and rest
3 Hair associated infections
- Folliculitis
- Furunculosis
- Carbuncles
What is Folliculitis
- Circumscribed, pustular infection of a hair follicle
- Presents as small red papules
- Typically found on head, back, buttocks and extremities
Most common cause of Folliculitis
Staph aureus
Furunculosis
- AKA boils
- Single haired follicle-associated inflammatory nodule e
- Usually affects moist, hairy, friction prone areas of body
Most common cause of Furunculosis and risk factors for it
Staph aureus
- Obesity
- Diabetes mellitus
- Atopic dermatitis
- Chronic kidney disease
- Corticosteroid use
What is a Carbuncle
Occurs when infection extends to involve multiple furuncles
Purulent material may be expressed from multiple sites
Treatment of Folliculitis, Furunculosis, Carbuncles
- Folliculitis = no treatment
- Furunculosis = no treatment (if no improvement oral antibiotics may be necessary)
- Carbuncles - Surgery and intravenous antibiotics
What is Necrotising Fasciitis
- A rare but serious bacterial infection that affects the tissue beneath the skin, and surrounding muscles and organs (fascia).
- Is one the infectious diseases emergencies, rapid onset
Types of Necrotising Fasciitis
- Type 1, mixed aerobic and anaerobic infection (diabetic foot infection, Fournier’s gangrene)
- Type 2, monomicrobial (normally associated with strep pyogenes)
Signs and symptoms of Necrotising Fasciitis
- Rapid onset
- Sequential development of erythema, extensive oedema and severe unremitting pain
- Haemorrhagic bullae, skin necrosis and crepitus
- Systemic features; fever, hypotension, tachycardia, delirium and multi-organ failure
- Anaesthesia at site of infection is highly suggestive of this disease
Management of Necrotising Fasciitis
- Surgical review is mandatory
- Imaging may help but delays treatment
- Antibiotics should be broad spectrum
Flucloxacillin
Gentamicin
Clindamycin - Mortality ranges between 17-40%
What is Pyomyositis + its presentation
- Purulent infection deep within striated muscle, often is an abscess
- Can present with fever, pain and woody induration of affected muscle
- If untreated can lead to septic shock + death
Most common cause of Pyomyositis
Staph aureus
Investigation for Pyomyositis
CT/MRI
Treatment of Pyomyositis
Drainage + Antibiotic cover
What is Septic Bursitis and how does it present
- Infection of bursae
- Often caused by infection from adjacent skin
- Peribursal cellulitis, swelling and warmth are common
- Fever + pain on movement also seen
Most common cause of Septic Bursitis + method of diagnosis
- Staph aureus
- Aspiration of fluid leads to diagnosis
What is Infectious Tenosynovitis
- Infection of the synovial sheet that surround tendons
- Most commonly affects Flexor muscle-associated tendons and tendon sheaths of the hand
- Presents with erythematous fusiform swelling
- Tenderness over length of tendon sheath + pain on extension of affected area
Most common cause of Infectious Tenosynovitis
Staph aureus and Streptococci
Treatment for infectious tenosynovitis
- Empiric antibiotics
- If hand is affected immediate review by surgeon
