Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Porphyria cutanea tarda ?
    ### Response:
    Porphyria cutanea tarda (PCT) is a form of porphyria that primarily affects the skin. People affected by this condition generally experience "photosensitivity," which causes painful, blistering lesions to develop on sun-exposed areas of the skin (i.e. the hands and face).
    