A Case Report: Kikuchi Disease Associated With a Positive Auto-Immune Panel Triggered by COVID-19 Infection.

Kikuchi disease (KD) is a rare, benign inflammatory condition characterized by fever and cervical lymphadenopathy. While the pathogenesis is largely unknown, Kikuchi disease onset has strong associations with various infections and autoimmune conditions. There are few reported cases of Kikuchi disease triggered by coronavirus disease 2019 (COVID-19) infection or vaccination. A 43-year-old Filipina female with a history of anemia and recent uncomplicated COVID-19 infection one month prior presented with a one-month history of progressive weakness, fatigue, anorexia with 30-pound weight loss, fevers, odynophagia, and new-onset hematemesis. Initial laboratory findings were most significant for a markedly elevated ferritin level prompting initial concern for hemophagocytic lymphohistiocytosis. Admission imaging revealed diffuse cervical and thoracic lymphadenopathy. Lymph node biopsy revealed paracortical expansion with numerous histiocytes with phagocytosed necrotic debris and germinal center necrosis, consistent with Kikuchi disease. She received supportive care without any medical intervention and improved clinically with the resolution of lymphadenopathy and inflammatory laboratory markers. This report describes the initial presentation and subsequent diagnostic workup of a unique and infrequently documented case of Kikuchi disease secondary to COVID-19 infection. This case highlights general constitutional symptoms, including fever and lymphadenopathy as defining characteristics of Kikuchi disease. During diagnostic workup, it is important to rule out hematologic emergencies, such as hemophagocytic lymphohistiocytosis, which can present similarly. This case also reports a concurrent autoimmune workup, which was positive at the time of the Kikuchi disease diagnosis. COVID-19 infections and deaths, while declining in the post-pandemic period, remain significant, thus diagnostic consideration for conditions of self-limited disorders, such as Kikuchi disease, should be considered.