Ecthyma gangrenosum is a rare cutaneous manifestation of a severe systemic infection caused by Pseudomonas aeruginosa, an opportunistic gram-negative bacteria. Opportunistic germs cause illness in people with weakened immune systems. As a result, the vast majority of ecthyma gangrenosum cases occur in persons who are critically ill or have a debilitated immune system. Ecthyma gangrenosum usually manifests with one or more skin lesions that quickly develop into necrotic ulcers, open sores containing an accumulation of dead tissue.
Ecthyma gangrenosum most often affects critically ill or immunocompromised individuals, such as people with leukemia, lymphoma, HIV infection, or severe burns. It can also occur in people taking immunosuppressive therapy and those who have undergone bone marrow transplantation. Ecthyma gangrenosum can develop in a healthy individual who does not have any other medical issues.