Treatment Antibiotics

Beta-haemolytic streptococci or Staphylococcus aureus causes almost all infections, so therapy must cover these.

Choice of antibiotics

Flucloxacillin is bacteriocidal against both organisms so is recommended as monotherapy for Class I (mild) infections at 500 mg four times a day, and for moderate (Class II and III) infections at a dose of 2 g four times a day (Level of evidence A III) [5].

Patients with Class IV infections need broad spectrum intravenous cover according to local guidelines (e.g. benzylpenicillin and ciprofloxacin).

Co-amoxiclav has a broad spectrum of activity and is therefore recommended for patients with cellulitis from bites (at a dose of 625 mg three times a day).

Ciprofloxacin 750 mg twice daily should be added to flucloxacillin to cover fresh water infections [7].

Recurrent cellulitis

About 29% of patients admitted with cellulitis have a recurrent episode within 3 years.
Recurrence is associated with chronic lymphoedema and venous eczema. Antibiotic prophylaxis should be considered for patients with recurrent cellulitis. Penicillin V 250 mg twice daily or erythromycin 250 mg twice daily have shown benefit in several small studies [10].