Drooping mouth corners, medically known as perioral ptosis or commonly as marionette lines, are facial features where skin folds extend downward from the outer corners of the mouth toward the chin. This downturned appearance can be interpreted as sadness or fatigue, even when the face is at rest. The formation of these lines results from a combination of mechanical, structural, and neurological factors. While many causes relate to the gradual process of aging, others involve acute medical events requiring immediate attention.
Age-Related Structural Changes
The most frequent cause of drooping mouth corners is the gradual structural breakdown that happens as part of the aging process. The skin’s structural proteins, collagen and elastin, begin to deplete and fragment, significantly reducing the skin’s natural elasticity and firmness. This loss of elasticity means the skin cannot resist the constant pull of gravity, allowing tissues to sag more noticeably over time.
Facial volume loss also plays a significant role in creating these prominent folds. Deep fat pads in the mid-face, such as the malar fat pad, experience atrophy and downward migration. This loss of support in the upper cheeks causes the overlying skin and soft tissue to descend, which in turn deepens the creases around the mouth area. This descent and resulting visible skin folding form the marionette lines.
Mechanical sagging is compounded by the constant pull of the facial musculature. The Depressor Anguli Oris (DAO) muscle pulls the mouth corner down and laterally. As supportive structures around the mouth weaken, the unopposed, persistent tension from the DAO muscle becomes more pronounced. This chronic downward contraction exaggerates the downturned look, significantly contributing to the appearance of perioral ptosis.
Acute Neurological Conditions
Sudden-onset drooping of the mouth corner signals a disruption in the facial nerve pathway and should be considered a medical emergency until serious causes are ruled out. A stroke, for instance, causes unilateral facial weakness, often resulting in a noticeable droop on one side of the face. This weakness is typically accompanied by other symptoms like arm weakness or slurred speech, occurring due to damage in the brain that controls the facial muscles.
Another common neurological cause is Bell’s Palsy, involving sudden, temporary paralysis or weakness of the facial muscles on one side, caused by inflammation or damage to the seventh cranial nerve. This condition develops rapidly and is characterized by a drooping corner of the mouth, difficulty closing the eye, and an inability to make certain facial expressions. Although Bell’s Palsy is typically temporary, immediate medical evaluation is necessary to distinguish it from a stroke and begin timely treatment, such as corticosteroids. Other localized nerve injuries, including those resulting from trauma or tumors, can also cause sudden facial weakness and subsequent mouth drooping.
External and Lifestyle Accelerants
While the underlying structural changes are unavoidable, several external and lifestyle factors can significantly accelerate the development of drooping mouth corners. Chronic exposure to ultraviolet (UV) radiation from the sun is a primary culprit, causing photoaging. UV rays penetrate the skin and break down collagen and elastin fibers at an increased rate, weakening the skin’s architecture much faster than natural aging alone.
Smoking also contributes to premature aging in the perioral region through multiple mechanisms. Nicotine causes vasoconstriction, reducing blood flow and oxygen supply to the skin, which impairs its ability to repair collagen. Furthermore, the repetitive pursing action required to smoke, combined with exposure to free radicals in the smoke, accelerates the formation and deepening of lines around the mouth. Inherited factors, such as jawbone shape or skin thickness, also influence a person’s predisposition to developing prominent marionette lines.
Clinical Approaches to Management
The clinical management of drooping mouth corners focuses on counteracting volume loss and muscular overactivity. Injectable dermal fillers, typically made of hyaluronic acid, are a common non-surgical approach used to restore lost volume. Fillers are strategically placed beneath the creases to physically lift the folds and provide structural support to the oral commissures, effectively shortening the marionette lines.
To address the active downward pull of the Depressor Anguli Oris muscle, neuromodulators like botulinum toxin (Botox) are injected directly into the DAO muscle. This treatment temporarily weakens the muscle, reducing its ability to pull the mouth corners downward. By relaxing the DAO, the mouth corners can achieve a more neutral or slightly elevated resting position, which helps to soften the sad or stern appearance.
For individuals with more advanced skin laxity and deeper folds, surgical options offer a more permanent solution. Procedures like a corner lip lift can physically elevate the downturned corners of the mouth by removing small amounts of skin and soft tissue. In cases of significant jowling and skin descent, a lower facelift may be necessary to reposition the underlying facial tissues and excise redundant skin, providing the most substantial and long-lasting correction.