Normally, vocal sounds are produced when air from the lungs is pushed past two side-by-side elastic muscles—called vocal folds or vocal cords—with sufficient pressure to cause them to vibrate. When the tumors interfere with the normal vibrations of the vocal folds, it causes hoarseness, which is the most common symptom of laryngeal papillomatosis. Eventually, the tumors may block the airway passage and cause difficulty breathing.

In adults, the symptoms of Laryngeal papillomatosis are hoarseness, or a strained or breathy voice. Size and placement of the tumors dictate the change in the person’s voice. Breathing difficulties may occur but more commonly are found in children.

In babies and small children the symptoms include a weak cry, difficulty swallowing, noisy breathing, and chronic cough. Noisy breathing may be a stridor, which can sound like a whistle or a snore, and is a sign that the laryngeal or tracheal parts of the airway are narrowing. The symptoms tend to be more severe in children than in adults.