What is the ruling on sufficing with tayammum instead of ghusl when there is a skin disease that causes severe swelling upon contact with water?

If the sister asking the question is harmed by using water for janabah (major ritual impurity) or wudu (ablution), she may perform tayammum (dry ablution), for Allah Almighty says: "And if you are ill or on a journey or one of you comes from the place of relieving himself or you have contacted women and find no water, then seek clean earth and wipe over your faces and hands."