December 14, 2018

Clinical morphologic testing in addition to tissue biopsy and culture are critical in distinguishing NND from NF and treating appropriately.

Lack of sufficient diagnostic criteria and biomarkers for distinguishing necrotizing neutrophilic dermatosis (NND) from necrotizing fasciitis (NF) may lead to inappropriate treatment that worsens the actual condition and prolongs disease morbidity, according to a study published in JAMA Dermatology.

In a case series of 54 patients diagnosed with NND at 3 academic institutions (University of California San Francisco, Oregon Health and Science University, and University of Minnesota) from January 1, 2015 to December 31, 2017, investigators found that 51 (94%) cases of NND were initially misdiagnosed as NF, resulting in patients receiving inappropriate treatment.

Of all the patients in the sample, 40 had pyoderma gangrenosum with systemic inflammation and 14 had necrotizing Sweet syndrome, both of which can mimic sepsis from severe infection (displaying symptoms of fever, leukocytosis, tachycardia, hypotension, and organ failure). The researchers found hematologic disorders and malignant neoplasms to be the most common disease associations in all 54 patients (n=18 [33%]), with myelodysplastic syndrome occurring in 9 patients (17%). Connective tissue disease (n=6 [11%]), endocrine disorders (n=7 [13%]), and inflammatory bowel disease (n=6 [11%]) were other common comorbidities. Potential medication triggers occurred in 7 patients (13%).

The most common cutaneous finding was erythema (n=41 [76%]), followed by other common findings of ulcers (n=25 [46%]) and necrosis (n=16 [30%]). Systemic findings included febrility (n=36 [67%]) and presentation of clinical signs resembling septic shock (n=14 [26%]). Cultures were taken in 45 cases (83%), of which 98% were negative. Elevated markers of systemic inflammation were found in 23 patients (43%), of leukocytosis in 36 patients (67%), and of leukomoid reaction in 15 patients (28%), with a mean (range) white blood cell count of 51371/μL (32,300-138,000/μL). 

The researchers also noted that “typical histopathologic findings were sparse diffuse subcutaneous and dermal inflammation with a predominance of neutrophils as well as associated leukocytoclasis and edema.” In 43% of cases, the neutrophilic infiltrate and associated necrosis often extended to the level of fascia or muscle.

Treatment therapies utilized in patients included debridement (n=42 [78%]), antibiotics (n=49 [91%]), systemic corticosteroids (n=50 [93%]), and limb amputations (n=4 [7%]). Additional immunosuppressants were used with some patients.

These findings suggest that clinical morphologic testing in addition to tissue biopsy and culture are critical in distinguishing NND from NF and treating appropriately.

This study design was limited by reliance on case reviews that were limited by publication bias of poor outcomes and missing information that affects results as well as by clinical descriptions of shock without use of formal Systemic Inflammatory Response Syndrome criteria.

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Reference

Sanchez IM, Lowenstein S, Johnson KA, et al. Clinical features of neutrophilic dermatosis variants resembling necrotizing fasciitis [published online October 31, 2018]. JAMA Dermatol. doi:10.1001/jamadermatol.2018.3890