Laryngitis happens when your vocal cords become swollen and inflamed, making your voice hoarse, raspy, or sometimes completely gone. The most common cause is a viral upper respiratory infection, like a cold or the flu, but plenty of non-infectious triggers can inflame your vocal cords too. Understanding what causes laryngitis comes down to three broad categories: infections, vocal strain, and environmental irritants.
Viral Infections Are the Most Common Cause
The vast majority of laryngitis cases start with a virus. If you’ve had a cold, the flu, or any upper respiratory infection, the same virus can spread inflammation down into your larynx (your voice box). This type of acute viral laryngitis is self-limiting, meaning it resolves on its own, typically within two to three weeks. You don’t need a special exposure. The same viruses circulating in offices, schools, and public transit that give you a stuffy nose and sore throat can settle into your vocal cords and steal your voice.
Bacterial laryngitis is far less common but more serious. The bacterium most frequently involved is Haemophilus influenzae, and unlike viral cases, bacterial infections of the larynx can become dangerous and require medical treatment. Bacterial laryngitis tends to come with more severe symptoms: high fever, difficulty swallowing, and rapidly worsening hoarseness.
Overusing Your Voice
Your vocal cords are two small folds of tissue that vibrate against each other hundreds of times per second when you speak. Shouting, singing for extended periods, talking loudly over background noise, or simply using your voice for hours without rest creates repeated collisions between the cords. Over time, this physical impact causes swelling and can even produce small lesions, nodules, or polyps on the vocal cord tissue. The medical term for this is phonotrauma.
You don’t have to be a professional singer to experience it. Cheering at a concert or sporting event, teaching a full day of classes, or talking over loud music at a bar for a few hours can be enough. Service-sector workers, who tend to use their voices more frequently on the job, show higher rates of voice disorders than the general population. The key factor isn’t volume alone but the combination of loudness, duration, and lack of vocal rest.
Acid Reflux That Reaches Your Throat
A lesser-known but surprisingly common cause of laryngitis is acid reflux that travels past your esophagus and into your throat. This condition, called laryngopharyngeal reflux (LPR), happens when both of the muscular valves guarding your esophagus fail to seal properly. Normally, a lower sphincter keeps stomach acid out of your esophagus, and an upper sphincter keeps it out of your throat. When both relax inappropriately, acidic stomach juices reach your larynx and irritate the delicate tissue there.
LPR is tricky because it doesn’t always feel like typical heartburn. Instead of chest burning and indigestion, it tends to show up as chronic hoarseness, a persistent need to clear your throat, a feeling of something stuck in your throat, or recurring laryngitis that doesn’t seem connected to a cold. If your voice keeps going hoarse without an obvious cause, reflux reaching your vocal cords is one of the more likely explanations.
Smoking and Chemical Irritants
Cigarette smoke, whether you’re the one smoking or breathing it in secondhand, contains toxic and carcinogenic substances that directly inflame the lining of your larynx. Chronic smoking is one of the most reliable ways to develop persistent laryngitis, and manufacturing workers exposed to industrial fumes and chemicals also face elevated risks of laryngeal problems, including higher rates of laryngeal cancer.
Other airborne irritants that can trigger or sustain laryngitis include chemical fumes from cleaning products or workplace solvents, dust, and allergens like pollen or mold. These substances don’t cause infection, but they provoke an inflammatory response in the larynx that produces the same hoarseness and discomfort. When the exposure is ongoing, the laryngitis becomes chronic rather than resolving in a few weeks.
Inhaled Medications
If you use a corticosteroid inhaler for asthma or COPD, your medication may be contributing to voice problems. Inhaled corticosteroids are effective at reducing airway inflammation, but residual medication depositing on the vocal cords can suppress the local immune response and allow fungal overgrowth, particularly Candida (the same organism behind oral thrush). This fungal laryngitis often goes undiagnosed because clinicians don’t always suspect it. Hoarseness and voice changes are the most frequently reported side effects of steroid inhalers, and fungal infection of the larynx is one possible underlying cause.
Alcohol and Dehydration
Alcohol is listed alongside chemical fumes and allergens as a recognized irritant that can cause chronic laryngitis. It works in two ways: alcohol directly irritates the mucosal lining of the throat and larynx, and it also dehydrates you. Your vocal cords need adequate moisture to vibrate smoothly. When they’re dry, the friction between them increases, making hoarseness and inflammation more likely. Heavy drinking compounds the problem by relaxing the lower esophageal sphincter, which increases acid reflux and makes LPR-related laryngitis more probable.
Acute Versus Chronic Laryngitis
The distinction matters because it points to different causes and different outcomes. Acute laryngitis lasts less than three weeks and is almost always triggered by a viral infection or a short burst of vocal strain. It resolves on its own with rest, hydration, and time.
Chronic laryngitis lasts longer than three weeks and signals an ongoing irritant: acid reflux, smoking, allergen exposure, occupational chemicals, or habitual vocal misuse. Over time, chronic laryngitis can lead to structural changes in the vocal cords, including the development of polyps or nodules that may require more involved treatment. If your voice stays hoarse past the three-week mark, the cause is almost certainly something beyond a simple cold, and identifying that underlying trigger is the key to getting it to resolve.