A 48-year-old woman comes to the emergency department due to a day of fever and skin rash. Eight months ago, the patient was found to have an adnexal mass and elevated CA-125 level. She underwent a hysterectomy with bilateral salpingo-oophorectomy and lymph node dissection. Histopathology showed serous carcinoma of the ovary, and she received adjuvant chemotherapy treatment. A recent imaging study revealed metastatic lesions in the liver, and a new chemotherapy regimen was administered a week ago. Temperature is 38.8 C (102 F), blood pressure is 110/60 mm Hg, and pulse is 114/min. Cardiopulmonary auscultation reveals no abnormalities other than tachycardia. The abdomen is nontender, and the surgical scars are well healed. The trunk has several indurated, nontender macules and pustules. Some of the lesions have become gangrenous ulcers. Complete blood count is as follows:
Hemoglobin 8.8 g/dL Platelets 102,000/mm3 Leukocytes 2,800/mm3
Which of the following is the most likely cause of this patient's skin lesions?
Patients on chemotherapy are often transiently immunocompromised due to cytotoxic effects on mature and immature immune cells putting them at risk for opportunistic pathogens. One of the most common opportunistic bacterial infections is the gram-negative bacillus Pseudomonas aeruginosa. Although Pseudomonas can affect a wide range of organ systems, a rare but characteristic cutaneous infection is ecthyma gangrenosum.
Ecthyma gangrenosum occurs primarily in immunocompromised patients with P aeruginosa bacteremia/sepsis. The organism invades the vascular media and adventitia, causing ischemic necrosis. Symptoms progress rapidly (over 12-18 hours) and manifest with cutaneous or mucous membrane lesions that begin as painless red macules and become indurated pustules/bullae, often with "punched-out" gangrenous ulcers. Most patients are febrile and ill, but occasionally no other signs or symptoms of infection are present.
P aeruginosa is the most common cause of ecthyma gangrenosum, but many other microorganisms can invade the vascular wall and result in similar lesions. As such, blood and exudate cultures should be sent, and broad-spectrum intravenous antibiotics should be initiated while awaiting culture results.
(Choice A) Multiple cutaneous metastases are unlikely to develop and progress into ulcers within a day. In addition, fever would be atypical unless secondary infection is present.
(Choice B) Drug hypersensitivity reactions such as Stevens-Johnson syndrome (SJS) may cause fever and skin necrosis. SJS lesions are typically painful, are often confluent, and begin as macules that progress to vesicles/bullae. Patients usually have several days of prodromal influenza-like symptoms. This patient with a day of rapidly progressive, nontender, gangrenous lesions is more likely to have ecthyma gangrenosum.
(Choice D) Varicella zoster virus can reactivate in immunocompromised patients and cause painful, unilateral vesicular eruptions (usually in a dermatomal distribution).
(Choice E) Pyoderma gangrenosum is a rare neutrophilic dermatosis most often seen in patients with inflammatory bowel disease and arthropathies. Lesions develop rapidly and begin as a cutaneous papule or nodule that quickly matures into a painful, purulent ulcer with violaceous borders. Fever is uncommon.
Educational objective:
Ecthyma gangrenosum is a rapidly progressive cutaneous disorder seen most commonly in immunocompromised patients with Pseudomonas aeruginosa bacteremia/sepsis. Lesions begin as painless red macules, quickly progress to pustules/bullae, and then form "punched-out" gangrenous ulcers. Patients are usually febrile and ill. Blood cultures and empiric, intravenous antibiotics are required.