Acute laryngitis is the most common cause of hoarseness and voice loss that starts suddenly. Most cases of acute laryngitis are caused by a viral infection that leads to swelling of the vocal cords. When the vocal cords swell, they vibrate differently, leading to hoarseness. The best treatment for this condition is to stay well hydrated and to rest or reduce your voice use. Serious injury to the vocal cords can result from strenuous voice use during an episode of acute laryngitis. Since most acute laryngitis is caused by a virus, antibiotics are not effective. Bacterial infections of the larynx are much rarer and often are associated with difficulty breathing. Any problems breathing during an illness warrants emergency evaluation.