Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Raynaud's Disease ?
    ### Response:
    Raynaud's disease is a rare disorder of the blood vessels, usually in the fingers and toes. It causes the blood vessels to narrow when you are cold or feeling stressed. When this happens, blood can't get to the surface of the skin and the affected areas turn white and blue.
    