Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) hidradenitis suppurativa ?
    ### Response:
    Hidradenitis suppurativa, also known as acne inversa, is a chronic skin disease characterized by recurrent boil-like lumps (nodules) under the skin. The nodules become inflamed and painful. They tend to break open (rupture), causing abscesses that drain fluid and pus.
    