noun (n)

• action that makes a problem or a disease (or its symptoms) worse(noun.act)

  Synonym:
  aggravation
  

  source: wordnet30
• violent and bitter exasperation(noun.act)

  Example:
  His foolishness was followed by an exacerbation of their quarrel.
  

  source: wordnet30
• The act rendering more violent or bitter; the state of being exacerbated or intensified in violence or malignity; as, exacerbation of passion.(noun)

  source: webster1913