Skin and Soft Tissue Infections 1

Question 1

What is Impetigo

Answer 1

• Superficial, highly infectious, skin infection
• Common in young children (hands, face and neck)
• Golden crust is highly suggestive of this diagnosis

Question 2

Most common cause of Impetigo

Answer 2

Staph aureus

Question 3

Predisposing factors for Impetigo

Answer 3

• Minor trauma
• Burns
• Poor hygiene
• Insect bites
• Chickenpox, eczema, atopic dermatitis

Question 4

Treatment for Impetigo

Answer 4

• Small areas = topical antibiotics

- Large areas = topical antibiotics + oral antibiotics e.g. Flucloxacillin

Question 5

What is Erysipelas

Answer 5

• Infection of upper dermis (most common in lower limbs)
• Painful red area (no central clearing)
• Associated fever
• Regional lymphadenopathy
• Typically has distinct elevated borders

Question 6

Most common cause of Erysipelas

Answer 6

Strep Pyogenes

Question 7

What is cellulitis

Answer 7

• 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

Question 8

Most likely cause of cellulitis

Answer 8

Staph aureus and Strep pyogenes

Question 9

Predisposing factors for cellulitis

Answer 9

• Diabetes mellitus
• Tinea pedis (athlete’s foot)
• Lymphoedema

Question 10

Treatment for cellulitis and erysipelas

Answer 10

• Anti-staphylococcal and anti-streptococcal antibiotics

- In extensive disease = IV antibiotics and rest

Question 11

3 Hair associated infections

Answer 11

• Folliculitis
• Furunculosis
• Carbuncles

Question 12

What is Folliculitis

Answer 12

• Circumscribed, pustular infection of a hair follicle
• Presents as small red papules
• Typically found on head, back, buttocks and extremities

Question 13

Most common cause of Folliculitis

Answer 13

Staph aureus

Question 14

Furunculosis

Answer 14

• AKA boils
• Single haired follicle-associated inflammatory nodule e
• Usually affects moist, hairy, friction prone areas of body

Question 15

Most common cause of Furunculosis and risk factors for it

Answer 15

Staph aureus

• Obesity
• Diabetes mellitus
• Atopic dermatitis
• Chronic kidney disease
• Corticosteroid use

Question 16

What is a Carbuncle

Answer 16

Occurs when infection extends to involve multiple furuncles

Purulent material may be expressed from multiple sites

Question 17

Treatment of Folliculitis, Furunculosis, Carbuncles

Answer 17

• Folliculitis = no treatment
• Furunculosis = no treatment (if no improvement oral antibiotics may be necessary)
• Carbuncles - Surgery and intravenous antibiotics

Question 18

What is Necrotising Fasciitis

Answer 18

• 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

Question 19

Types of Necrotising Fasciitis

Answer 19

• Type 1, mixed aerobic and anaerobic infection (diabetic foot infection, Fournier’s gangrene)
• Type 2, monomicrobial (normally associated with strep pyogenes)

Question 20

Signs and symptoms of Necrotising Fasciitis

Answer 20

• 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

Question 21

Management of Necrotising Fasciitis

Answer 21

• Surgical review is mandatory
• Imaging may help but delays treatment
• Antibiotics should be broad spectrum
  Flucloxacillin
  Gentamicin
  Clindamycin
• Mortality ranges between 17-40%

Question 22

What is Pyomyositis + its presentation

Answer 22

• 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

Question 23

Most common cause of Pyomyositis

Answer 23

Staph aureus

Question 24

Investigation for Pyomyositis

Answer 24

CT/MRI

Question 25

Treatment of Pyomyositis

Answer 25

Drainage + Antibiotic cover

Question 26

What is Septic Bursitis and how does it present

Answer 26

• Infection of bursae
• Often caused by infection from adjacent skin
• Peribursal cellulitis, swelling and warmth are common
• Fever + pain on movement also seen

Question 27

Most common cause of Septic Bursitis + method of diagnosis

Answer 27

• Staph aureus

- Aspiration of fluid leads to diagnosis

Question 28

What is Infectious Tenosynovitis

Answer 28

• 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

Question 29

Most common cause of Infectious Tenosynovitis

Answer 29

Staph aureus and Streptococci

Question 30

Treatment for infectious tenosynovitis

Answer 30

• Empiric antibiotics

- If hand is affected immediate review by surgeon