Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Stevens-Johnson syndrome ?
    ### Response:
    What are the signs and symptoms of Stevens-Johnson syndrome? Often, Stevens-Johnson syndrome begins with flu-like symptoms, followed by a painful red or purplish rash that spreads and blisters, eventually causing the top layer of the skin to die and shed. To be classified as Stevens-Johnson syndrome, the condition must involve less than 10% of the body surface area.
    