Supplementary Material for: Treatment of a complex case of scleromyxedema using a novel IVIg preparation

Abstract
Introduction: We provide a case report on a patient with scleromyxedema treated with high-dose intravenous immunoglobulins (IVIg) who reported less fatigue and fewer headaches after transitioning to Yimmugo, a novel IVIg preparation. Scleromyxedema is a rare and chronic cutaneous mucinosis, frequently associated with monoclonal gammopathy and systemic complications, which may be life-threatening. The disease is characterized by papular eruptions and sclerosis of the skin. Treatment of skleromyxedema is challenging because of its unclear pathogenesis. High-dose intravenous immunoglobulins (IVIg) are a promising treatment option to improve cutaneous manifestations.
Case presentation: We present the case of a 57-year-old patient with scleromyxedema and monoclonal gammopathy with end stage renal failure on haemodialysis (three times a week). Stabilization of skin symptoms was finally achieved by high-dose IVIg therapy administered at 2g per kg bodyweight distributed over two days every three weeks. However, disease stabilization came at the expense of flu-like side effects that significantly affected daily life. After transitioning to Yimmugo® the patient reported an improved quality of life.
Conclusion: Further follow-up is essential to conclusively evaluate effectiveness and tolerability of this novel IVIg preparation.