Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Lymphedema ?
    ### Response:
    Lymphedema is the name of a type of swelling. It happens when lymph builds up in your body's soft tissues. Lymph is a fluid that contains white blood cells that defend against germs. It can build up when the lymph system is damaged or blocked. It usually happens in the arms or legs.
    