Hyperinflammatory proliferative (blastomycosis-like) pyodermas: review, mechanisms, and therapy.

Some sites of chronic localized infection have a vigorous granulocytic inflammatory response and develop marked tissue proliferation. This is most common in patients with poor nutrition, halogen ingestion or foreign bodies. The granulocytes release connective tissue-activating peptides which cause fibroblast proliferation and ground substance formation. The dermal papillae enlarge and support a larger germinative cell volume, producing pseudoepitheliomatous hyperplasia. Hypertrophic granulation tissue or "proud flesh" appears to be a similar phenomenon without the epithelial component. In a milder physiologic range this phenomenon probably accounts for the term "laudable pus."