People who suffer from laryngitis either experience chronic or acute symptoms. Chronic laryngitis is more severe, as it is long term, whereas acute is short term. Essentially, laryngitis occurs when the vocal cords or voice box become inflamed due to overuse or infection, but chronic laryngitis is caused by environmental factors that continually irritate the vocal cords. Other causes of chronic laryngitis include frequent sinus infections, acid reflux, smoking, and more.