add insult to injury vs irritate

add insult to injury

verb
  • To further a loss with mockery or indignity; to worsen an already unfavourable situation. 

irritate

verb
  • To provoke impatience, anger, or displeasure in. 

  • To cause or induce displeasure or irritation. 

  • To induce pain in (all or part of a body or organism). 

How often have the words add insult to injury and irritate occurred in a corpus of books? (source: Google Ngram Viewer )