[13] Impetigo Flashcards
What is impetigo?
A very common superficial infection of the skin
How can impetigo be divided?
- Bullous form
- Non-bullous form
What form of impetigo accounts for the majority of cases?
Non-bullous
How else can impetigo be classified?
- Primary
- Secondary
What is primary impetigo?
Where impetigo occurs in intact skin
What is secondary impetigo?
Where impetigo occurs in skin already affected by another condition
How is impetigo spread?
Direct contact with lesions or with nasal carriers
What is the incubation period of impetigo?
- 1-3 days in Streptococcus
- 4-10 days in Staphylococcus
What can cause lesions to spread in the individual?
Scratching
What are the common causative organisms of non-bullous impetigo?
- Staphylococcus aureus
- Streptococcus pyogenes
What is an increasingly common cause of non-bullous impetigo?
MRSA
What is bullous impetigo invariably caused by?
Staph. aureus
What are the risk factors for impetigo?
- Age 2-5
- Attending school or daycare
- Diabetes mellitus
- Dermatitis
- Immunodeficiency disorders
- Warm climate
How do non-bullous impetigo lesions present?
Tiny pustules or vesicles that evolve into honey-coloured crusted plaques
What is the typical size of the plaques in non-bullous impetigo?
< 2cm
Where do non-bullous impetigo lesions usually occur?
- Face (around mouth and nose)
- Extremities (at breaks in the skin)
How quickly can non-bullous impetigo spread on the skin?
Rapidly
What can occur due to auto-inoculation in non-bullous impetigo?
Satellite lesions
How much erythema and oedema will surround a non-bullous impetigo lesion?
Little to none
Is non-bullous impetigo itchy?
Can be
How may regional lymph nodes appear in non-bullous impetigo?
Enlarged
Describe bullous impetigo lesions
Thin roofed bullae that rupture spontaneously with little erythema
Where do bullous impetigo lesions usually appear?
- Face
- Trunk
- Extremities
- Buttocks
- Perineum
What is bullous impetigo more likely to occur alongside?
Other disease e.g. atopic eczema
What other symptoms are often present in bullous impetigo?
- Pain
- Malaise
How is impetigo usually diagnosed?
Clinically
What tests may be useful in managing impetigo?
Swabs
When may swabs be useful in impetigo?
- Extensive or severe
- MRSA suspected
- Recurrent or failing to respond
What are the differentials for non-bullous impetigo?
- Contact dermatitis
- Herpes simplex
- Discoid lupus
- Scabies
What are the differentials for bullous impetigo?
- Other bullous skin diseases
- Burns
- Necrotising fasciitis
How can impetigo be managed?
- General advice
- Antibiotics
What general advice should be given to patients with impetigo?
- Good hygiene measures
- Stay off school/work until lesions are dry and scabbed over or on antibiotics for 48 hours
What good hygiene measures should be followed in impetigo?
- Keep affected area clean
- Wash hands after touching
- Don’t share towels or bathwater
- Avoid scratching
If impetigo is mild what antibiotics can be used?
Topical fusidic acid TDS for 5 days
If impetigo is widespread of bullous what antibiotics can be used?
Oral flucloxacillin QDS for 7 days
What are the potential compliations of impetigo?
- Cellulitis
- Lymphangitis
- Suppurative lymphadenitis
- Stahpylococcal scalded skin syndrome
What are the further potential complications of impetigo caused by Group A beta haemolytic strep?
- Scarlet fever
- Glomerulonephritis
