Kikuchi–Fujimoto Disease in Children: Case Report and Diagnostic Insights

Kikuchi–Fujimoto disease (KFD) is a rare condition marked by subacute necrotizing lymphadenopathy and fever. Although its exact cause remained unknown, researchers proposed an immune-mediated mechanism that could explain its frequent association with systemic lupus erythematosus (SLE). Histological features included histiocytic necrosis with abundant nuclear debris, without neutrophils or eosinophils. Immunohistochemistry typically showed MPO-positive and CD68-positive histiocytes, T-cell predominance, and CD123-positive plasmacytoid dendritic cells near necrotic areas.

Although previously thought to affect mainly young adults, increasing pediatric cases suggested it was not uncommon in children. Some studies also reported a higher frequency of cutaneous rashes in pediatric patients.

This report described an 11-year-old girl with a month-long fever (up to 39 °C) and cervical lymphadenopathy. She had a similar episode a month prior, which responded to IV methylprednisolone. During her current hospitalization, she developed erosive and crusted lesions on her face and ears. Kaposi's varicelliform eruption was suspected, and PCR for herpes simplex virus was done. While awaiting results, she was treated empirically with IV linezolid and acyclovir, with no significant improvement.

PCR tests were negative. Lab tests showed leucopenia and mild inflammation. Serologies were negative except for Mycoplasma IgM and positive antinuclear antibodies (ANA). A skin biopsy revealed a nonspecific lymphocytic infiltrate, while lymph node histology confirmed necrotizing lymphadenitis. KFD was diagnosed. IV methylprednisolone led to symptom resolution, and the patient was discharged on oral prednisone. She later started hydroxychloroquine and remained symptom-free at one-month follow-up.

KFD should be considered in febrile children with lymphadenopathy, especially when skin findings are present.

(Source: Dermatopathology. 2025; 12(1):7. https://doi.org/10.3390/dermatopathology12010007)