We experienced a case of discoid lupus erythematosus (DLE) associated with Epstein-Barr virus (EBV) infection with Kikuchi disease. The patient, a 7-year-old boy, was initially diagnosed with Kikuchi’s disease based on lymph node histology. The symptoms were resolved after initiation of glucocorticoid therapy; however, on discontinuation of the therapy, exudative erythema appeared on the cheeks, palms, and soles with recurrence of fever and deterioration of cervical lymphadenopathy. At the time of initial examination, EBV-VCA-IgG and whole blood EBV-DNA levels were high and EBNA was negative, suggesting a primary EBV infection. A cervical lymph node biopsy showed evidence of Kikuchi’s disease. The general findings improved spontaneously; whereas the erythema on the cheeks persistently worsened. Further serological examinations revealed positive results for anti-Sm, anti-Ro, anti-RNP, and anti-DNA antibodies. Based on the clinical findings and skin biopsy, the patient was finally diagnosed with discoid lupus erythematosus. Erythema improved with topical tacrolimus, and subsequently EBV-DNA became less sensitive and all the autoantibodies became negative. We hypothesized that EBV infection associated with Kikuchi’s disease leads to the production of autoantibodies and the subsequent development of DLE, which has a molecular mechanisms similar to Kikuchi’s disease.

Interstitial lung disease (ILD) caused by systemic lupus erythematosus (SLE) includes acute lupus pneumonitis (ALP). We report two cases of ALP as initial symptom of SLE. The first patient was 7-year-old girl with a history of 8-month dyspnea preceding the diagnosis of SLE. Chest CT showed bilateral ground-glass opacity (GGO) in lower lobes. After treatment for 4 weeks, GGO disappeared. The second patient was 14-year-old girl who had no respiratory symptoms at the diagnosis of SLE, but CT scan showed small consolidation in right lower robe. Like the first patient, consolidation was improved after treatment for 4 weeks. ALP has various subtypes from asymptomatic to critically ill. ALP occurs accompanied by other major organ damage such as lupus nephritis. On the other hand, it can precede other organ symptoms in some cases in which diagnosis of SLE is more difficult than typical ones. It is important to consider SLE as a differential diagnosis of ILD and to assess for ILD even among patients of SLE without obvious respiratory symptoms.

We report a severe case of coronavirus disease 2019 (COVID-19)-related multisystem inflammatory syndrome in children (MIS-C). A 9-year-old girl who was diagnosed with acute abdomen by appendicitis underwent appendectomy. During anesthetic induction, unexpected hypotension occurred, and she required continuous noradrenaline administration. Pathological examination showed nonspecific findings. She showed KD-like findings such as indurative edema of the extremities, conjunctivitis, and cervical lymphadenopathy on admission. Owing to a history of COVID-19 1 month prior to admission, she was suspected to have MIS-C and treated with intravenous immunoglobulin and methylprednisolone therapy. A variety of symptoms have been reported in MIS-C cases, and in our case acute abdomen and shock were seen at onset. Thus, we need to consider MIS-C as a differential diagnosis when there is a history of COVID-19 with prolonged fever and abdominal symptoms.