Mixed Connective Tissue Disease Presenting as Diabetic Ulcer in a 52 Year Old Female Patient: A Case Report

Mixed connective tissue disease (MCTD) is a rare and complex autoimmune condition characterized by overlapping features of systemic lupus erythematosus (SLE), systemic sclerosis, polymyositis/dermatomyositis, and rheumatoid arthritis. Due to the varied clinical presentation and the absence of validated classification criteria, early diagnosis can be challenging, often leading to misclassification or delayed recognition. Here, we report a case of a 52-year-old female with MCTD and vasculitis, underscoring the importance of considering uncommon autoimmune etiologies in patients with non-healing ulcers. The patient presented with skin tightening, Raynaud’s phenomenon, and chronic non-healing ulcers, initially attributed to diabetic complications. Diagnostic evaluation revealed high-titre anti-U1-RNP antibodies, confirming MCTD. Treatment with oral steroids, cyclophosphamide, and sildenafil led to significant clinical improvement, particularly in ulcer resolution. This case emphasizes the critical need for early intervention and a multidisciplinary approach in managing autoimmune vasculitis associated with MCTD to prevent progression and optimize patient outcomes.