Morphea skin disease does cause skin to change colors, according to Mayo Clinic. It causes purplish or reddish patches on the skin and causes areas of skin to look darker or lighter than the adjacent skin.
Morphea, which is a type of scleroderma, not only changes the color of a patient's skin, but changes the texture, says Mayo Clinic. Scleroderma means "hard skin," and morphea causes the skin to become thick and hard. It also causes the affected skin to lose sweat glands and hair.
Morphea also causes oval patches on the skin that change color and eventually have a white center, says Mayo Clinic. Long patches also appear on the patient's arms and legs. These are called en coupe de sabre, according to MedicineNet.