Diagnosis: Ecthyma Gangrenosum

Destin, Fla. -- The patient was "profoundly neutropenic," but her vital signs were stable. Laboratory tests revealed an absolute neutrophil count of 0, a platelet count of 30,000, and a hemoglobin level of 9.2 gm/dL.

"Keeping the differential broad in neutropenic patients is important," noted Dr. Lauren C. Hughey, who is with the University of Alabama in Birmingham.

The differential diagnosis in this case included Sweet's syndrome, or acute febrile neutrophilic dermatosis, bacterial abscess, deep fungal infection, viral illness, vasculitis, or an adverse drug reaction, she said at a meeting of the Alabama Dermatology Society.

"She had neutropenic fever, and we needed help figuring out where it was coming from," Dr. Hughey said. Initial therapy covered all three possible infections: fungus, virus, and atypical mycobacteria.

In a case like this, always consider doing two biopsies, one for hematoxylin and eosin (H&E) and another for tissue cultures, including acid-fast bacilli and bacteria and fungus.

A punch biopsy revealed epidermal necrosis and sloughing with abundant gram-negative bacilli. The patient had septic vasculitis, demonstrated by the bacilli that were clustered in collarettes that surrounded necrotic blood vessels. Her blood culture grew Pseudomonas aeruginosa.

The diagnosis was ecthyma gangrenosum.

"Dermatologists can save lives by initiating double antibiotic therapy early," Dr. Hughey said.

Mortality is high with ecthyma gangrenosum--an estimated 10%-38%, especially if there is associated bacteremia, multiple skin lesions, a delay in antibiotic initiation, or prolonged neutropenia.

Double antibiotic therapy with an aminoglycoside and beta-lactam penicillin is warranted for these patients, she explained.

The woman in this case received piperacillin/tazobactam (Zosyn, Wyeth; plus generic) and gentamicin (multiple generic forms). The patient's outcome is unknown.

"In neutropenic patients, skin findings can be atypical," Dr. Hughey said at the meeting.

Ecthyma gangrenosum often presents as purpuric macules that quickly progress to hemorrhagic bullae and necrotic ulcers with black crusts.

One pearl is to remember ecthyma gangrenosum as a cause of hemorrhage bullae in the perineal area, she added.

Erythematous macules, papules, and nodules are other skin findings. Although the characteristic lesions most often appear in the perineal and gluteal areas, they can appear anywhere, including on the extremities. Lesions typically are very few in number.

Fever, hypotension, and tachycardia and other clinical signs of sepsis are typically observed.

Dr. Hughey had no relevant financial disclosures to report.

--Damian McNamara