Kikuchi-Fujimoto disease following COVID-19 infection in a 13-year- old girl

ABSTRACT

Background/Purpose: Kikuchi-Fujimoto disease (KFD) is a rare, self-limited histiocytic necrotizing lymphadenitis. Although it is of uncertain aetiology, it is associated with viral infections and autoimmune diseases. Hence, it is crucial to identify KFD from other conditions with lymphadenopathy. Here we present a case of KFD after COVID-19 infection. Method(s) Medical records were traced and reviewed Results: A previously healthy 13-year- old girl was admitted in April 2022 with four weeks of fever, dry cough, loss of weight, followed by 1 week history of painful cervical lymphadenopathy and nonspecific maculopapular rash. She received her second dose of Covid 19 vaccine in January 2022. Unfortunately, she was diagnosed with CAT II, COVID 19 infection in March 2022. There was no history of allergy, recent traveling and cat scratch injury. Clinically there was no strawberry tongue, erythema of the lips, conjunctivitis or distal extremities changes to suggest Kawasaki disease. She was initially diagnosed with infection related lymphadenitis, treated with oral azithromycin for three days and intravenous ceftriazone for one week with no improvement. Her laboratory results showed hypochromic microcystic anaemia with leucopenia, raised inflammatory markers and lactate-dehydrogenese levels. Extensive workup for infection was unremarkable. Immunology test showed ANA, ANCA, ENA were negative with normal complements. Ultrasound abdomen was normal. Excisional lymph node biopsy revealed confluent areas of necrosis surrounded by histiocytes (CD68+) with absent of neutrophils. No granuloma or atypical lymphoid cells seen. Based on histopathology report, diagnosis of KFD was established. As she was not able tolerate orally, IV hydrocortisone was started and subsequently switched to oral prednisolone. She responded well to corticosteroids with fever subsided within a day and cervical lymphadenopathy reducing in size and resolved in one month. Prednisolone was able to taper off by two months. She showed complete recovery with no recurrence during follow-up. Conclusion(s) In persistent febrile painful lymphadenopathy, excision lymph node biopsy is essential to establish definite diagnosis. This case highlights the possible association between COVID-19 and KFD.