Case report of subcutaneous granuloma annulare preceding idiopathic juvenile arthritis
Introduction (case reports only) Subcutaneous granuloma annulare (SGA) is a rare clinical form of granuloma annulare (GA) that predominantly affects children. While the cause of GA is yet unknown, recent studies show that there might be a link between GA and autoimmune disorders. Cases of GA triggered by SARS-CoV-2 have also been reported. Because of the various morphology of lesions, a biopsy is the most accurate diagnostic tool. Case description (case reports only) We present a 2-year-old girl with a suddenly occurred left knee swelling, accompanied by a circular, not painful rash on both ankles with small subcutaneous nodules. Blood tests did not show inflammation. ANA test was positive. Ultrasound of the joints has shown effusion in the left knee, and heterogenous subcutaneous lesions, in the rash projection, with increased Doppler signal. NSAIDs were prescribed for knee arthritis with positive effect. After 6 months nodules enlarged significantly after the girl had a Covid-19 infection. The skin biopsy confirmed the diagnosis of SGA. Due to the tendency of spontaneous resolution the specific treatment was not necessary, and the granulomas disappeared in a few months. Unfortunately, at 4 years old the patient came back with typical signs of juvenile idiopathic arthritis (JIA) in the left knee. Intraarticular glucocorticoid injection was done and treatment with methotrexate was started. Summary (case reports only) We describe a case of a 2-year-old girl with SGA preceding JIA. SGA nodules enlarged significantly after Covid-19 infection. JIA was diagnosed 2 years after the first SGA nodules emerged. Conclusions SGA can be misdiagnosed because of the lack of overlying cutaneous changes. Thus, histopathological examination is important to confirm the diagnosis and rule out other disorders. Usually, GA does not require treatment and disappears within two years. However, GA can precede other autoimmune diseases.