Impetigo

Question 1

Define impetigo and what are the types

Answer 1

Superficial bacterial infection of the skin:

Non-bullous: majority of cases (70%)
Bullous: formation of fluid filled lesions, usually >5mm in diameter

Question 2

What is the aetiology of impetigo

Answer 2

Can develop as a primary infection in otherwise healthy skin OR a secondary complication of pre-existing skin conditions e.g. eczema, scabies, chickenpox
Transmission is via close contact with an infected person or indirectly via contaminated objects e.g. toys, clothing, towel

Organisms:
Staphylococcus aureus
Streptococcus pyogenes
Mixed
MRSA

Question 3

What are the risk factors for impetigo

Answer 3

Skin trauma
Pre-existing skin disease e.g. eczema, scabies, chickenpox
Hot/humid weather
Poor hygiene
Crowding

Question 4

What are the symptoms of non-bullous impetigo

Answer 4

Skin lesion:
- begins as thin walled vesicle/pustule → releases exudate
- Becomes a golden/brown crust
- most commonly peri-oral, peri-nasal, limbs, flexures
± satellite lesions
Mild pruritus
Severe: lymphadenopathy, fever

Otherwise asymptomatic

Question 5

What are the symptoms of bullous impetigo

Answer 5

Skin lesion
- Flaccid, fluid-filled vesicles and blisters
- Blister ruptures → thin flat yellow/brown crust
- Most commonly flexures, face, trunk, limbs
Fever
Lymphadenopathy
Diarrhoea
Weakness

Question 6

What are the differentials for impetigo

Answer 6

Cellulitis
Erysipelas
Scalded skin syndrome
Necrotising fasciitis
Candidiasis
Herpes simplex
Bullous pemphigoid
Pemphigus vulgaris

Question 7

What are the investigations for impetigo

Answer 7

Clinical diagnosis

± Swab of lesion for MC&S (widespread cases, recurrent cases, or those that persist despite treatment)

Question 8

What is the management for localised non-bullous impetigo

Answer 8

1. Explain diagnosis and give information (British association of Dermatologists)
2. Re-assure: heals without scarring
3. Advice:
   - Wash affected areas with soap and water
   - Wash hands regularly
   - Avoid scratching
   - Avoid sharing towels, face cloths, care products
   - Thoroughly clean toys and equipment
4. School exclusion recommended - until lesions are healed and crusted over OR 48h after Abx initiation
5. Pharmacological:
   First line: Hydrogen peroxide 1% cream (2-3x daily for 5 days)
   Second line: topical fusidic acid

+ follow up

Question 9

What is the management for widespread non-bullous and bullous impetigo

Answer 9

1. Explain diagnosis and give information (British association of Dermatologists)
2. Re-assure: heals without scarring
3. Advice:
   - Wash affected areas with soap and water
   - Wash hands regularly
   - Avoid scratching
   - Avoid sharing towels, face cloths, care products
   - Thoroughly clean toys and equipment
4. School exclusion recommended - until lesions are healed and crusted over OR 48h after Abx initiation
5. Pharmacological:
   First line: oral flucloxacillin 4x a day for 5 days
6. Consider referral

+ follow up

Question 10

What are the complications of impetigo

Answer 10

Acute glomerulonephritis (streptococcal)
Cellulitis
Staphylococcal scalded skin syndrome
Lymphangitis
Osteomyelitis
Septic arthritis
Septicaemia
Scarlet fever, urticaria, erythema multiforme (streptococcal)

Question 11

What is the prognosis of impetigo

Answer 11

Usually a self-limiting condition that takes 2-3 weeks to clear if untreated
Appropriate antibiotic treatment leads to rapid resolution infection, reducing the infective period
Relapse occurs often in people with underlying skin conditions e.g. eczema, and staphylococcal carriers
Impetigo can lead to life-threatening complications in some cases .g. immunosuppression, neonates