Furuncles and carbuncles

Necrotising perifollicular infection, usually due to Staphylococcus aureus. Risk factors include: nasal carriage of S. aureus, maceration, breaks in the skin, poor hygiene; diabetes mellitus, malnutrition, iron deficiency or immunodeficiency.

Clinical features

• Furuncle: red, warm, painful nodule with a central pustule, usually around a hair follicle. It becomes fluctuant, discharges a core of purulent exudate, and leaves a depressed scar. It occurs most frequently on the thighs, groin, buttocks, armpits, neck and back. There is no fever.
• Carbuncle: a cluster of interconnected furuncles, sometimes with fever and peripheral lymphadenopathy. It leaves a depressed scar.

Treatment

• Single furuncle:
  • Clean with soap and water 2 times daily and cover with a dry dressing.
  • Apply warm moist compresses to the furuncle in order to encourage it to drain.
  • After drainage, clean and apply a dry dressing until the lesion has healed.

• Furuncle on the face, multiple furuncles, carbuncles or in immunocompromised patients:
  • Same local care.
  • Add systematically an antibiotic for 7 days a Citation a. For penicillin-allergic patients:
    clindamycin PO (children: 10 mg/kg 3 times daily; adults: 600 mg 3 times daily) : 
    cefalexin PO
    Neonates under 7 days: 25 mg/kg 2 times daily
    Neonates 7 to 28 days: 25 mg/kg 3 times daily
    Children 1 month to 12 years: 25 mg/kg 2 times daily
    Children 12 years and over and adults: 1 g 2 times daily
    or 
    amoxicillin/clavulanic acid (co-amoxiclav) PO. Use formulations in a ratio of 8:1 or 7:1. The dose is expressed in amoxicillin:
    Children < 40 kg: 25 mg/kg 2 times daily
    Children ≥ 40 kg and adults: 
    Ratio 8:1: 2000 mg daily (2 tablets of 500/62.5 mg 2 times daily)
    Ratio 7:1: 1750 mg daily (1 tablet of 875/125 mg 2 times daily)

• In all cases: wash hand frequently, wash bedding.