Ecthyma gangrenosum

Ecthyma gangrenosum is an infection of the skin typically caused by Pseudomonas aeruginosa that is a round or oval 1- to 15-cm lesion with a halo of erythema and usually with a necrotic center representing where the organism has invaded blood vessels and produced hemorrhagic infarctions. These ulceritic lesions are single or multiple and heal with scar formation.