cGVHD is a major problem after allogeneic HSCT. Skin is the most frequently affected organ, and manifestations are highly variable reflecting the four anatomic levels of skin involvement. In the severe form when damage and fibrosis affects all skin layers, deep multiple variable-sized open wounds appear. It is unknown if ischemia due to damaged dermal and subcutaneous layers plays a role in such ulcer formation. Herein, we report a patient with severe open wound skin cGVHD. His lesions were tested by transcutaneous continuous oximetry in consideration for HBOT. The ulcers studied were proven to be non-ischemic.