Impetigo (Bacterial Skin infection)

Question 1

Background

Answer 1

Common superficial bacterial infection of the skin. acute and contagious. Transmission happens from direct close contact.
Most common in children esp. in hot and humid climate.
2 forms:
- Bullous - caused by Staphylococcus aureus
- Non-bullous is caused by S. aureus, group A Streptococcus (Streptococcus pyogenes), or a combination of both

Predisposing factors:
- climatic conditions (humidity, occlusive clothing),
- underlying skin disease (atopic - dermatitis, hidradenitis suppurativa),
- iron deficiency,
- DM,
- defective neutrophil function (treated with oral vitamin C) or
- immunodeficiency, eg hypo-gamma-globulinaemia and HIV infection

Question 2

Signs and Symptoms / Diagnosis

Answer 2

Non-bullous impetigo:
Lesions begin as thin walled vesicles or pustules - release exudate making crust. - Heals 2-3 weeks

bullous impetigo:
Lesions appear as flaccid fluid filled vesicles and blisters (2/3 days). Blisters rupture leaving a thin flat yellow/brown crust. Heals 2-3 weeks

Diagnosis:
History taking, Examine for signs and symptoms, can take swabs

If recurrent infection take SWABS.

Question 3

Treatment

Answer 3

Non pharmacological:
Good hygiene (washes regular, avoid scratches and sharing towels/cloths).

Pharmacological:
localised non-bullous impetigo:
- Hydrogen peroxide 1% cream (apply 2/3times daily - 5 days NOT systemically unwell or at high risk complications
ALT 5 days - topical antibiotic:
- Fusidic acid 2% TDS, OR
- Mupirocin 2% TDS if fusidic acid unsuitable.
Can increase to 7 days
SAME for children

widespread non-bullous impetigo:
5 days - topical or oral antibiotic - not systemically unwell or at high risk of complications.
- Topical fusidic acid 2% TDS, or
- Mupirocin 2% TDS if fusidic acid

Resistance is suspected or confirmed, OR
Adults, oral flucloxacillin 500mgQDS, Unsuitable - ALT =
- Clarithromycin 250mg BD (dosage can be increased to 500mg BD - severe infections), OR
- Erythromycin (in pregnancy) 250-500 mg QDS.
Can increase to 7 days

Bullous impetigo, or impetigo in people, who are systemically unwell or at high risk of complications:
SKIP to oral antibiotics (Same for children)

Question 4

Treatment children

Answer 4

widespread non-bullous impetigo:
ALL 5 days
- Oral flucloxacillin (62.5–125mg QDS 1 month-1 year; 125–250mg QDS - 2–9 years; 250–500mg QDS - 10-17 years)
Unsuitable ALT:
- Clarithromycin (1 month -11 years: <8 kg, 7.5mg/kg BD; 8–11 kg, 62.5mg BD; 12–19kg, 125mg BD; 20–29kg, 187.5mg BD; 30–40kg, 250mg BD. 12–17 years, 250mg BD). OR
- Erythromycin 250–500 mg QDS 8–17 years.
Can increase to 7 days