MedicineNet explains laryngitis is only contagious if the cause of an inflamed larynx is from an infection, such as an upper respiratory infection, the common cold, or other viruses that spread due to aerosol droplets. WebMD states laryngitis can also be caused by bacterial infections; however, an inflamed larynx caused by overuse of the voice or cancer is not contagious.
Spreading infectious laryngitis can be prevented by covering the nose and mouth when coughing and sneezing. Frequent handwashing also prevents germ transmission between people. MedicineNet reveals wiping down door handles and not sharing utensils also helps prevent germs from going person to person.
Doctors diagnose laryngitis when a combination of upper respiratory infection with a hoarse voice exists. Patients answer the doctor's questions and have the ears, nose and throat examined, according to MedicineNet. If a throat infection is involved, a doctor may test for strep throat. A swollen neck, shortness of breath and difficulty swallowing may also indicate laryngitis.
The University of Michigan states laryngitis can also be caused by irritants from smoking, acid reflux and chemicals. Treatment for laryngitis includes hydration, a humidifier, not speaking, drinking warm beverages and gargling salt water. Severe cases of laryngitis may lead to bleeding of the vocal cords or polyps on the organ.