Ecthyma Gangrenosum – 6 Interesting Facts
- An acute onset of erythematous macules or patches, later with ulceration and hemorrhage, in a patient with neutropenia or another form of immunosuppression, should raise suspicion of ecthyma gangrenosum (EG).
- EG usually affects the axillary skin, anogenital skin, and skin of the lower extremities.
- A CBC to determine neutropenia is always indicated.
- Monotherapy is usually with an antipseudomonal antibiotic, such as ceftazidime, imipenem, or cefepime.
- Polytherapy may involve an antipseudomonal aminoglycoside plus an antipseudomonal β-lactamase penicillin (e.g., piperacillin) or ticarcillin-clavulanate potassium.
- EG is a serious infection, with mortality rates in the literature of over 30% and as high as 90% in some series.
Etiology and Risk Factors
- Ecthyma gangrenosum (EG) is an infection consisting of sepsis and localized skin necrosis, with the latter at one or more sites.
- Classic forms of the disease involve neutropenic patients, with the most frequently implicated bacteria being Pseudomonas aeruginosa, followed by Serratia, Escherichia coli, Klebsiella pneumoniae, and other gram-negative organisms.
- Some cases of EG are polymicrobial and, in addition to gram-negative bacteria, another gram-positive bacteria may also be involved in the infection.
Diagnosis
Approach to Diagnosis
- An acute onset of erythematous macules or patches, later with ulceration and hemorrhage, in a patient with neutropenia or another form of immunosuppression, should raise suspicion of EG.
Workup
Physical Examination
- Patients with EG are usually neutropenic, with the total white blood cell count usually less than 250 cells/mcL.
- Rarely, patients have a normal white blood cell count, but there may be other contributory diseases (e.g., HIV infection, hypogammaglobinemia, lymphoma).
- Signs and symptoms of a systemic infection, including fever, malaise, lassitude, are often present.
- EG usually affects the axillary skin, anogenital skin, and skin of the lower extremities.
- Single or multiple lesions may be present.
- Primary lesions are edematous red macules or patches that rapidly progress to hemorrhagic bullae. Mature lesions demonstrate an eschar or ulcer, with a rim of erythema.
Laboratory Tests
- A CBC to determine neutropenia is always indicated.
- Gram staining of an aspirate or touch prep will demonstrate numerous bacteria and provide information as to whether this is a gram-positive, gram-negative, or polymicrobial infection.
- Culture blood, aspirate, and biopsy material.
Diagnostic Procedures
- A 3- or 4-mm punch biopsy is characteristic, with millions and billions of bacteria typically identified, often with little or no inflammation because the patient is usually neutropenic.
Treatment
Nondrug and Supportive Care
- Correction of the neutropenia or another cause of immunosuppression is useful, if possible.
Drug Therapy
- Monotherapy is usually with an antipseudomonal antibiotic, such as ceftazidime, imipenem, or cefepime.
- Polytherapy may involve an antipseudomonal aminoglycoside plus an antipseudomonal β-lactamase penicillin (e.g., piperacillin) or ticarcillin-clavulanate potassium.
- If an infected catheter is suspected, there are chemotherapy-induced oral ulcers, known gram-positive species are present, or the patient is already on fluoroquinolone, vancomycin is often added.
References
1.Vairman M, et al. Ecthyma gangrenosum and ecthyma-like lesions: review article. Eur J Clin Microbiol Infect Dis. 2015;34:633-639.
