DR15.1-3 | Pyoderma — Glossary

A broad-spectrum beta-lactam/beta-lactamase-inhibitor combination useful where beta-lactamase-producing or mixed organisms are likely.

A superficial pyoderma marked by flaccid bullae from Staphylococcus aureus exfoliative toxin cleaving desmoglein 1 in the upper epidermis.

A coalescence of adjacent furuncles into a deep, multi-headed abscess; commonly on the nape of the neck or back, and frequent in diabetics.

A deep bacterial infection of the dermis and subcutaneous tissue producing ill-defined, flat, spreading erythema with warmth, tenderness, and often fever.

A first-generation cephalosporin active against Staphylococcus and Streptococcus, used as a systemic option for pyoderma.

A lincosamide active against many community-acquired MRSA strains; carries a notable risk of Clostridioides difficile colitis and must pass a negative D-zone test before reliance.

Penicillinase-resistant penicillins; first-line systemic agents for methicillin-susceptible staphylococcal pyoderma.

Trimethoprim-sulfamethoxazole; an MRSA-active oral agent whose adverse effects include rash (with risk of severe cutaneous reactions), marrow suppression, and hyperkalaemia.

A crackling sensation felt on palpation of the skin, caused by gas produced by gas-forming organisms; a late sign suggestive of necrotising soft-tissue infection.

A disc-diffusion test that detects inducible clindamycin resistance; a positive result means clindamycin may fail despite apparent in-vitro susceptibility.

A tetracycline MRSA-active oral agent; adverse effects include photosensitivity and dental staining (contraindicated in young children and pregnancy).

A deeper, ulcerative form of impetigo with a thick adherent crust over a punched-out ulcer; heals with scarring.

A Streptococcus pyogenes infection of the upper dermis and lymphatics presenting as a sharply-demarcated, raised, hot red plaque, typically on the face or leg, with fever.

A Staphylococcus aureus toxin (ET-A/ET-B) that cleaves desmoglein 1 in the upper epidermis, producing the blistering of bullous impetigo and SSSS.

A soft, compressible quality on palpation indicating a collection of pus within a cavity; the clinical threshold for incision and drainage of a furuncle or carbuncle.

Superficial infection of the hair follicle producing small follicular pustules pierced by a hair.

A necrotising soft-tissue infection of the perineum and genital/scrotal region; a urological-surgical emergency requiring urgent debridement.

A deep, tender follicular abscess with a single pus-point, caused by Staphylococcus aureus at hair-bearing, friction-prone sites.

A topical antibiotic inhibiting bacterial protein synthesis (elongation factor G), used for localised superficial staphylococcal pyoderma; carries a risk of contact dermatitis and resistance.

A chronic inflammatory condition of apocrine-gland-bearing skin producing recurrent abscesses and sinus tracts that may need surgical drainage or excision.

The commonest superficial pyoderma; honey-coloured crusted erosions, typically peri-oral/peri-nasal in children, caused by Staphylococcus aureus with or without Streptococcus pyogenes.

The surgical opening and evacuation of a pus-filled abscess cavity; the primary intervention for a fluctuant furuncle or carbuncle, providing source control that antibiotics cannot.

Laboratory Risk Indicator for Necrotising Fasciitis — a scoring aid using laboratory values to estimate the risk of necrotising infection; an adjunct that must not override strong clinical suspicion.

A Staphylococcus aureus strain resistant to anti-staphylococcal beta-lactams via an altered penicillin-binding protein; treated with clindamycin, doxycycline, or cotrimoxazole in skin infection.

A topical antibiotic that inhibits bacterial isoleucyl-tRNA synthetase; first-line topical agent for localised impetigo and nasal Staphylococcus aureus decolonisation.

A necrotising soft-tissue infection involving the deep fascia; Type I is polymicrobial and Type II is caused by Group A Streptococcus; requires emergency surgical debridement.

A rapidly progressive, life-threatening infection spreading along fascial planes with tissue death; a surgical emergency requiring immediate debridement, of which necrotising fasciitis is the prototype.

Pain markedly greater than the visible skin changes would explain; the most important early warning sign of necrotising soft-tissue infection, often preceding skin necrosis.

A pyogenic (pus-forming) bacterial infection of the skin, caused predominantly by Staphylococcus aureus and Streptococcus pyogenes.

The physical removal of an infective focus — by drainage of pus or debridement of dead tissue — that antibiotics alone cannot eliminate.

A toxin-mediated disease, mainly of young children, with widespread tender erythema and superficial peeling from haematogenous spread of staphylococcal exfoliative toxin.

A coagulase-positive, Gram-positive cluster-forming coccus; the dominant cause of most pyodermas and the producer of exfoliative toxins responsible for bullous impetigo and SSSS.

Group A beta-haemolytic Streptococcus; a Gram-positive chain-forming coccus that spreads through dermis and lymphatics, causing erysipelas and some cellulitis.

The surgical removal of dead and infected tissue; the definitive source-control procedure for a necrotising soft-tissue infection.

The decision to involve a surgeon in a patient's care because the condition requires a procedure — here, drainage or debridement — that medical therapy alone cannot achieve.

Features such as high fever, tachycardia, hypotension, and altered mental state indicating that a local infection has become a systemic (septic) threat and warranting urgent surgical review.