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SAPHO (Synovitis Acne Pustulosis Hyperostosis and Osteitis) syndrome is a rare autoinflammatory condition characterized by bone inflammation (aseptic osteitis) and skin manifestations, such as palmoplantar pustulosis, acne, and pustular psoriasis. 1 Due to its often subtle and variable presentation, SAPHO syndrome is frequently misdiagnosed, especially in patients with comorbid inflammatory bowel disease (IBD).2 Since 1992, cases of SAPHO syndrome associated with IBD have been reported, though only a few paediatric cases have been documented.2 3 Here, we present a unique case of SAPHO syndrome developing in an adolescent with Crohn’s disease, highlighting the diagnostic and therapeutic challenges associated with overlapping autoimmune diseases.An 8-year-old girl was seen in the paediatric Gastroenterology clinic with symptoms of chronic diarrhoea, angular stomatitis. Her Faecal calprotectin was >1800. Endoscopy and histology revealed multifocal Crohn’s disease-Stomach, Duodenum, ileum and Colon (Paris Classification A1b, L3 + L4a, B1, G0)After diagnosis, the patient achieved remission with Modulen and corticosteroids. However, maintenance therapy with azathioprine proved ineffective in maintaining clinical remission and Infliximab was initiated. Due to ongoing symptoms her IFX dose was increased to 10 mg/kg every 8 weeks, and azathioprine was discontinued. She maintained sustained clinical and biochemical remission after optimising the IFX therapy.At age 11, three years after her Crohn’s diagnosis, she developed psoriatic skin lesions, including palmar psoriasis and plaques on her knees, elbows, scalp, and legs. Dermatology initially suspected an anti-TNF-induced skin reaction; however, the diagnosis was revised to psoriasis, and topical therapy with steroid and emollients was started. Around the same period, she developed painful swelling at the medial end of the right clavicle, presenting with warmth, mild tenderness, and persistent erythema. Radiological studies revealed chronic recurrent multifocal osteomyelitis (CRMO) of the right sternoclavicular joint, fulfilling the Kahn criteria for a diagnosis of SAPHO syndrome.1 4 Due to her stable Crohn’s disease and the onset of SAPHO-related symptoms, infliximab was discontinued at age 12. However, as pain in her clavicles, knee, and elbow intensified, she received a Zolendronic acid infusion for symptom relief. With her Crohn’s disease in remission, she was switched to weekly subcutaneous methotrexate (15 mg/m²).Over the past two years, the patient has maintained a stable clinical course, with sustained clinical and biochemical remission of her Crohn’s disease and complete resolution of osteoarticular and dermatological manifestations.This case underscores the complexity of diagnosing and managing SAPHO syndrome in paediatric patients with Crohn’s disease. SAPHO syndrome can mimic anti-TNF skin reactions, adding diagnostic challenges in IBD patients.3 5 Methotrexate proved effective in managing SAPHO in this patient and may offer an effective alternative therapy allowing for sustained remission of both Crohn’s disease and SAPHO symptoms.3 Biologic swap could be considered to Adalimumab if Methotrexate alone does not provide adequate maintenance therapy for Crohn’s. Multidisciplinary collaboration and individualized therapy are essential in managing the intersecting pathways of autoinflammatory and autoimmune conditions in paediatric patients.References Chamot AM, Benhamou CL, Kahn MF, et al. Acne-pustulosis- hyperostosis-osteitis syndrome. Results of a national survey 85 cases. Rev Rhum Mal Osteoartic. 1987;54:187–196.Naves JE, Cabré E, Manosa M, Grados D, Olivé A, Domènech E. Asystematic review of SAPHO syndrome and inflammatory bowel disease association. Dig Dis Sci. 2013 Aug;58(8):2138–47.Marrani E, et al. SAPHO syndrome in pediatric patients with inflammatory bowel disease treated with infliximab. Dig Liver Dis. 2018. https://doi.org/10.1016/j.dld.2018.09.001 Kotilainen PM, Laxen FO, Manner IK, et al. An aseptic inflam- mation of the clavicle in a patient with Crohn’s disease. A potential manifestation of the SAPHO syndrome. Scand J Rheumatol. 1996;25:112–114.Rukavina I. SAPHO syndrome: a review. J Child Orthop. 2015 Feb;9(1):19–27.