Vocal cord polyps are benign, non-cancerous growths that form on the vocal folds inside the larynx. They typically present as a single, fluid-filled, or sometimes hemorrhagic lesion on one vocal cord. This condition is common among individuals who frequently strain or overuse their voice, leading to changes in voice quality like hoarseness, breathiness, or vocal fatigue. The formation of these growths is a direct result of mechanical trauma to the vocal folds.
The Core Cause: Acute Vocal Cord Trauma
The primary driver for the development of a vocal cord polyp is an acute mechanical injury event known as phonotrauma. This involves the excessive force or misuse of the voice, causing unusually violent collisions between the vocal folds. The collision forces are highest at the midpoint of the vocal cord, the most common site for polyp formation.
This acute trauma can lead to the rupture of a small blood vessel underneath the vocal cord’s surface, triggering a localized hemorrhage. The resulting blood-filled blister or lesion develops into a vocal cord polyp. This type of polyp is often referred to as a hemorrhagic polyp due to its origin from bleeding within the superficial layer of the vocal fold tissue.
Polyps are distinct from vocal nodules, which are usually bilateral, symmetrical, and more like calluses that form over time from chronic friction. In contrast, a polyp is typically a solitary, blister-like, or fluid-filled mass that results from a single acute traumatic event. The localized swelling and fluid accumulation interfere with the vocal cord’s wave-like vibration, causing the characteristic hoarseness and voice changes.
Specific High-Risk Vocal Behaviors
The mechanical trauma that initiates polyp formation is directly linked to specific, high-impact vocal behaviors. These actions force the vocal folds to slam together with excessive energy. Chronic yelling or screaming, especially over loud noise, is a common trigger because it drastically increases the force of vocal fold collision.
Other forms of vocal misuse that create high shear forces include excessive and forceful throat clearing or coughing. These actions subject the vocal cord tissue to sudden, intense pressure changes and friction. Professional voice users, such as singers, teachers, or salespeople, are at increased risk if they employ sustained poor singing or speaking techniques.
Using the voice at an unnaturally high or low pitch for extended periods also forces the vocal mechanism to operate inefficiently, leading to greater muscle strain and vocal cord impact. These high-risk behaviors create the necessary physical conditions for a microvascular injury to occur. An episode of severe voice abuse can lead to the sudden formation of a polyp that changes the voice overnight.
Systemic and Environmental Contributing Factors
While mechanical trauma is the direct cause, several systemic and environmental factors increase the vocal cords’ susceptibility to injury. Laryngopharyngeal Reflux (LPR), often called silent reflux, is a significant contributor because stomach acid and digestive enzymes travel up to the throat and irritate the vocal cords. The acid exposure makes the vocal fold lining swollen and inflamed, which lowers the threshold for injury from even moderate voice use.
Chronic exposure to inhaled irritants further compromises vocal cord health by causing persistent inflammation. This includes smoking, vaping, and working in dusty or chemically polluted environments. Smoking, in particular, is strongly associated with a specific type of polyp called Reinke’s edema, which involves a gelatinous swelling of the vocal folds.
Dehydration is another major contributing factor, as it reduces the natural lubrication, or mucus blanket, that protects the vocal folds. When the vocal cords are dry, they become stiffer and more brittle, increasing the friction and shear stress during vibration. This lack of protective moisture makes the tissue far more vulnerable to trauma.