Ecthyma gangrenosum is a potentially life-threatening Infection of Skin in patients who are immunocompromised through disease or immunosuppressive therapy. It is most commonly caused by Pseudomonas aeruginosa though a variety of other organisms may be implicated. It is characterized by usually painless erythematous macules or plaques which progress to haemorrhagic blistering and necrosis of the skin. Lesions may be multiple and widely disseminated, though the anogenital area is a common site. Pseudomonas can frequently be cultured from the blood.