DR15.1-2 | Pyoderma Presentation and Antimicrobial Treatment — Summary & Reflection

KEY TAKEAWAYS

Pyoderma is a pyogenic bacterial skin infection caused predominantly by Staphylococcus aureus and Streptococcus pyogenes, classified by depth and mechanism. Superficial types: non-bullous impetigo (honey-crust, Staph ± Strep), bullous impetigo (Staph exfoliative toxin), and ecthyma (deeper, ulcerative). Follicular types: folliculitis, furuncle (boil), and carbuncle (coalescing furuncles, common in diabetics). Spreading types: erysipelas (Streptococcus pyogenes; sharply-demarcated, raised plaque, face/leg) and cellulitis (ill-defined, deep). SSSS occurs in young children from haematogenous exfoliative toxin and needs admission. Diagnosis is clinical; culture is reserved for recurrent, treatment-failure, or MRSA-suspect cases, with a D-zone test before relying on clindamycin. Topical therapy (mupirocin, fusidic acid) suits localised superficial disease — watch for local irritation, sensitisation, and emerging resistance. Systemic therapy treats extensive, deep, spreading, or toxic disease: anti-staphylococcal beta-lactams (cloxacillin/dicloxacillin, cephalexin, amoxiclav) first-line; a macrolide if penicillin-allergic; and an MRSA-active agent (clindamycin, doxycycline, or cotrimoxazole) when resistance is suspected — each with its own adverse-reaction profile to counsel about. Reading the lesion accurately and matching it to the right drug and route is the core competency.

REFLECT

Think back to a skin infection you have seen during your clinical postings — perhaps an impetiginised child in paediatrics, a boil in a diabetic, or a 'red leg' admitted as cellulitis. Looking back with what you now know, was the lesion correctly identified by its morphology and depth, and was the choice of topical versus systemic therapy and the specific drug appropriate to the likely organism and the patient's allergy status? If you were the prescriber, what would you have counselled the patient about adverse reactions, and how would you have decided whether a culture was needed? Connecting each prescription you witness to the reasoning chain — lesion, organism, route, drug, adverse reaction — is the discipline that turns textbook knowledge into safe, resistance-conscious practice.