| Ecthyma gangrenosum | |
|---|---|
_ecthyma.jpg) | |
| Specialty | Infectious diseases |
Ecthyma gangrenosum is a type of skin lesion characterized by vesicles orblisters, which rapidly evolve intopustules andnecroticulcers with undermined tendererythematous border. "Ecthyma" means a pus-forming infection of the skin with an ulcer, "gangrenosum" refers to the accompanying gangrene or necrosis. It is classically associated withPseudomonas aeruginosa bacteremia, but it is notpathognomonic.[1]Pseudomonas aeruginosa is a gram negative, aerobic bacillus.[2]
This type of skin lesion was first described in association withPseudomonas aeruginosa by L. Barker in 1897.[3] It was given the name "ecthyma gangrenosum" by Hitschmann and Kreibich.[4]
It mostly occurs in patients with underlying immunocompromise (e.g.malignancy orHIV). Although most cases are due toP. aeruginosa infection, recent reports of this skin lesion associate it with other microorganisms, such asEscherichia coli,Citrobacter freundii,Klebsiella pneumoniae, various otherPseudomonas species, andMorganella morganii.[3]
The primary skin lesion usually starts with amacule that is painless, round, and erythematous. Then, it develops into a pustule, and then abulla with a central hemorrhagic focus. The bulla progresses into an ulcer, which extends laterally. Finally, it becomes a gangrenous ulcer with a central blackeschar surrounded by an erythematous halo.[4] The lesions may be single or multiple. They are most commonly seen inperineum and underarm pit, but they can occur in any part of the body.[4]
The organism enters directly through the breakdown of mechanical defense barriers such asmucosa or skin. Conditions that lead to the development of an immunocompromised state make the patient more susceptible to ecthyma gangrenosum andsepsis.[4] In case of sepsis, the bacteria reach the skin via the bloodstream. Defectivehumoral orcellular immunity increases risk, as the organisms are not cleared from the bloodstream as usual. The main mechanism of the organism that is causing the typical skin lesions is the invasion of the organism into the arteries and veins in thedermis and subcutaneous tissues of the skin. Thisperivascular invasion leads to nodular formation, ulceration, vasculitis, and necrosis due to impaired blood supply. Perivascular involvement is achieved by direct entry of bacteria through the skin orhematogenous spreading in case of sepsis.[4]
Diagnosis is made by clinicalobservation and these tests:[citation needed]
Magnetic resonance imaging can be done in case of ecthyma gangrenosum ofplantar foot to differentiate fromnecrotizing fasciitis.[4]
The main organism associated with ecthyma gangrenosum isP. aeruginosa. Multibacterial cases are reported, as well. Prevention measures include practicing proper hygiene, educating the immunocompromised patients for awareness to avoid possible conditions, and seeking timely medical treatment.[4]
Treatments involve antibiotics that cover forP. aeruginosa.Antipseudomonal penicillins,aminoglycosides,fluoroquinolones, third-generationcephalosporins, or ceftriaxoneaztreonam can be given. Usually, the antibiotics are changed according to the culture and sensitivity results.[4] In patients with very low white blood cell counts,granulocyte-macrophage colony-stimulating factor may be given. Depending on the causal agents, antivirals or antifungals can be added.[4]
Surgery is needed if extensive necrosis is not responding to medical treatments.[citation needed]
A recent retrospective study of all cases of ecthyma gangrenosum from 2004 to 2010 in a university hospital in Mexico shows thatneutropenia in immunocompromised patients is the most common risk factor for ecthyma gangrenosum.[5]