Diagnostic Role of Direct Immunofluorescence Assay in Determining The Etiology of Erythroderma: Experience in a Tertiary Referral Hospital

INTRODUCTION: Erythroderma is a life-threatening dermatologic emergency which is characterized by diffuse erythema and exfoliation affecting more than 90% of the body surface area. Most common cutaneous diseases associated with erythroderma are systemic contact dermatitis, psoriasis, drug eruption and atopic dermatitis. Clinical-pathological correlation is used to determine the underlying disease. In addition, direct immunofluorescence (DIF) may provide significant clues for etiology of erythroderma especially in the case of autoimmune bullous skin diseases (ABSDs). OBJECTIVES: In our study, we aimed to analyze the demographic data, clinical pre-diagnoses, final diagnosis, histopathological and DIF examination findings, accompanying systemic signs and laboratory abnormalities of erythrodermic patients. METHODS: We conducted a retrospective study of 31 erythroderma patients in a referral hospital between 2014 and 2021. Cutaneous biopsies were taken from all patients for H&E and DIF examination. RESULTS: Average age was 54.6 ± 23 years, 48.4% of the patients were female (N = 15) whereas 51.6 % of the patients were male (N = 16). Average time between the onset of rash and biopsy was 18.8 days. DIF analysis showed immune deposits in 19.4% (N = 6) of the patients; whereas no immune deposits were detected in 80.6% (N = 25) of the patients. The most frequent final diagnosis was adverse cutaneous drug eruption followed by ABSDs. CONCLUSIONS: Our findings suggest that DIF may be used in conjunction with clinical-pathologic and clinical findings to reveal the associated skin diseases in erythrodermic patients. Erythrodermic patients presenting with clinical findings of ABSD should be considered for DIF examination.