Bilateral Iselin’s Disease: A Rare Case of Midfoot Pain and Swelling in a Paediatric Female

Abstract Iselin’s disease, a traction apophysitis at the base of the fifth metatarsal, is a rare cause of lateral midfoot pain in children. This report describes a rare case of bilateral Iselin’s disease in an 8-year-old girl presenting with bilateral foot pain and swelling for 3 months, aggravated by physical activity. Examination revealed tenderness and swelling near the proximal fifth metatarsal. Imaging showed a bony fragment along the fifth metatarsal base with adjacent soft-tissue oedema, confirming Iselin’s disease. Blood tests indicated low Vitamin D (24 ng/mL) and Vitamin B12 (159 pg/mL) levels, with other markers normal. Management included analgesics, calcium and Vitamin D supplements and 2 weeks of immobilisation with below–knee casts. By 12 weeks, the patient reported a marked reduction in pain and swelling. This case highlights the importance of considering Iselin’s disease in the differential diagnosis of lateral midfoot pain in paediatric patients.