A virus is usually what causes the inflammation.
Typical symptoms include hoarseness and loss of voice.
The diagnosis is based on symptoms and changes of the voice.
Usually, resting the voice and avoiding any irritants are adequate treatment.
Causes of Laryngitis
The most common cause of short-lived (acute, lasting less than 3 weeks) laryngitis is
Laryngitis also may accompany bronchitis Acute Bronchitis Acute bronchitis is inflammation of the windpipe (trachea) and the airways that branch off the trachea (bronchi) caused by infection. Acute bronchitis is usually caused by a viral upper respiratory... read more or any other inflammation or infection of the upper airways. Excessive use of the voice, allergies, inhalation of certain medications, or irritants such as cigarette smoke can cause acute or persistent (chronic) laryngitis. Bacterial infections of the larynx are extremely rare.
Chronic laryngitis, in which symptoms last longer than 3 weeks, also may be caused by gastroesophageal reflux Gastroesophageal Reflux Disease (GERD) In gastroesophageal reflux disease, stomach contents, including acid and bile, flow backward from the stomach into the esophagus, causing inflammation in the esophagus and pain in the bottom... read more 
and, less commonly, by lingering bronchitis. People with bulimia Bulimia Nervosa Bulimia nervosa is an eating disorder characterized by the repeated rapid consumption of large amounts of food (binge eating), followed by attempts to compensate for the excess food consumed... read more who vomit frequently may develop laryngitis.
Symptoms of Laryngitis
Symptoms of laryngitis are an unnatural change of voice, such as hoarseness or a decrease in volume, or even loss of voice that develops within hours to a day or so. The throat may tickle or feel raw, and a person may have a constant urge to clear the throat.
Symptoms vary with the severity of the inflammation. Fever, a general feeling of illness (malaise), difficulty in swallowing, and a sore throat may occur in severe infections.
Diagnosis of Laryngitis
A doctor's evaluation
Sometimes direct inspection with a mirror or a viewing tube
Sometimes evaluation for cancer
The diagnosis of laryngitis is based on the typical symptoms and voice changes.
In chronic laryngitis, the doctor looks down the throat with a mirror or a thin, flexible viewing tube, which shows some reddening and sometimes some swelling of the lining of the larynx.
Because cancer of the larynx may cause hoarseness, a person whose symptoms persist more than a few weeks should be evaluated for laryngeal cancer Laryngeal Cancer Laryngeal cancer is cancer originating in the larynx, also known as the voice box. People may be hoarse or have a lump in the neck or difficulty breathing or swallowing. A biopsy is needed for... read more .
Treatment of Laryngitis
Resting the voice, cough suppressants, extra fluids, and steam
Treatment of the cause
Treatment of viral laryngitis depends on the symptoms. Resting the voice (by not speaking), taking cough suppressants, drinking extra fluids, and inhaling steam relieve symptoms and help healing. Whispering, however, may irritate the larynx even more. Stopping smoking and treating bronchitis, if present, may alleviate laryngitis.
An antibiotic is given only for infection caused by bacteria.
Depending on the possible cause, specific treatments to control gastroesophageal reflux, bulimia, or drug-induced laryngitis may be helpful.
