Scleredema is a rare disease, affecting the skin connective tissue with increased amounts of collagen and glycosaminoglycans. In the present study, the collagen synthesis and re-epithelialisation rate were measured from a 64-year-old male patient, who rapidly developed extensive tightening of the skin, without any underlying disease. The skin was thickened at several sites when measured with ultrasound, and the histology revealed accumulation of glycosaminoglycans and collagen bundles. The collagen synthesis rate was measured from suction blisters induced on two different sites of the skin before the treatment and three times later up to 6 months after the treatment with a systemic steroid was started. The aminoterminal propeptide of type I collagen (PINP) was increased manifold in the affected skin when compared with the controls, indicating active collagen deposition in vivo. Systemic steroid medication with high doses (over 20 mg/d) decreased both the type I and the type III collagen propeptide levels. The time schedule of the decreases in the propeptides in the thickened, affected skin and in the clinically normal-looking skin varied, and especially in the thickened skin in the abdomen the decrease in PINP was noted only after 3 months of prednisolone therapy. When the prednisolone dose was only 10 mg daily, the propeptides were again up-regulated, perhaps reflecting the natural course of the disease. The re-epithelialisation rates at two different sites of the patient were similar to those in the controls, suggesting that even massive fibrosis with active deposition of collagen does not alter the basal rate of re-epithelialisation in the skin. In conclusion, collagen synthesis is markedly elevated in scleredema, leading to fibrosis of the skin. A recently developed method utilizing assays of collagen propeptides from suction blister fluid allows monitoring of the collagen synthesis and detection of changes in the collagen synthesis during the treatment of fibrotic disorders.