Neutrophil-to-lymphocyte ratio is a prognostic predictor in emergency department patients with cutaneous adverse drug reaction.

Abstract

We aimed to evaluate the prognostic value of neutrophil-to-lymphocyte ratio (NLR) in emergency department (ED) patients with cutaneous adverse drug reactions to identify the severe patients at an early stage. In this retrospective study, patients aged 18 and over who admitted to the ED of a university hospital with the diagnosis of cutaneous adverse drug reaction were included. For included patients, clinical findings and ED admission complete blood count results were recorded. The primary outcome was hospitalization and the secondary outcome was the type of drug reaction. A total of 135 patients were included in the study. The median age of patients was 50 (36-64) years. There was no significant difference between the patients hospitalized and discharged from the ED in terms of age and gender (p = 0.340 and p = 0.762, respectively). There was no significant difference between hospitalized and discharged patients in terms of complete blood count parameters (p > 0.05, for all). The median NLR of hospitalized patients was significantly higher than that of patients discharged from the ED (6.13 vs. 3.69, p = 0.006). The median NLR of the patients with erythema multiform/Steven Johnson syndrome/toxic epidermal necrosis was significantly higher than the NLR of the patients with maculopapular and fixed drug eruptions (p = 0.022 and p = 0.015, respectively). The area under the curve value of NLR in predicting hospitalization was 0.640 (0.546-0.734). For 8.4 of NLR cutoff value, specificity was 83.9%. NLR is a useful and simple prognostic parameter as an indicator of systemic inflammatory involvement in ED patients with cutaneous adverse drug reactions. NLR is a useful parameter for deciding which patient will be admitted to the hospital in that patient group.