Causes and Symptoms of Facial Paralysis: A Comprehensive Overview

Facial paralysis, also known as facial nerve palsy or Bell's palsy in Western medicine, is a condition that affects the muscles on one side of the face, leading to temporary or, in some cases, long-term loss of facial movement. Understanding its causes and recognizing early symptoms are crucial for timely diagnosis and effective treatment. This article explores the underlying factors from both traditional Chinese medicine (TCM) and modern medical perspectives, along with a detailed look at common clinical manifestations.

Different Perspectives on the Causes of Facial Paralysis

Traditional Chinese Medicine (TCM) Viewpoint

In Traditional Chinese Medicine, facial paralysis is believed to stem from a deficiency in "Zheng Qi" — the body's vital energy or immune resistance. When this protective energy weakens, external pathogenic factors such as wind-cold or wind-heat can invade the body, particularly affecting the meridians that run through the face. This disruption blocks the flow of qi and blood in the facial channels, resulting in impaired muscle control and ultimately causing facial drooping. TCM practitioners often associate sudden onset with exposure to cold drafts, air conditioning, or weather changes, especially when the body is already fatigued or under stress.

Western Medical Explanation

From a biomedical standpoint, facial paralysis is primarily attributed to inflammation or damage to the facial nerve (cranial nerve VII), a condition medically termed facial neuritis. It can be classified into two main types: central and peripheral (or peripheral) facial paralysis. Most common cases fall under peripheral facial paralysis, which occurs when the facial nerve is damaged anywhere from the brainstem to its branches in the face. This type is often linked to viral infections—such as herpes simplex virus—leading to swelling and compression of the nerve within the narrow bony canal of the skull. Other potential causes include trauma, tumors, Lyme disease, or diabetes-related neuropathy.

Recognizing the Key Symptoms of Facial Paralysis

The hallmark sign of facial paralysis can be summarized in four words: "drooping of the mouth and eye". This phrase captures the most visible and distressing symptoms experienced by patients, typically appearing suddenly—often overnight.

Oral and Mouth-Related Symptoms

One of the first signs many people notice is an asymmetrical smile or difficulty controlling facial movements around the mouth. Patients may find it hard to puff out their cheeks or whistle, as the muscles on the affected side fail to respond. The corner of the mouth tends to droop toward the unaffected (healthy) side, creating a lopsided appearance. Additionally, involuntary drooling and trouble keeping food inside the cheek during eating are common complaints. These issues arise due to weakened orbicularis oris and buccinator muscles, which play key roles in lip closure and oral coordination.

Eye and Forehead Manifestations

Eye symptoms are equally prominent and can lead to complications if not managed properly. The inability to fully close the eyelid on the affected side—known as lagophthalmos—is a major concern. This leaves the cornea exposed, increasing the risk of dryness, irritation, and even corneal ulcers. Patients may also experience reduced or absent forehead wrinkling when trying to raise their eyebrows, indicating involvement of the frontal branch of the facial nerve. Ptosis-like appearance (though not true ptosis) may occur due to eyebrow drooping, further contributing to a tired or uneven facial expression.

In some cases, individuals report additional sensations such as facial numbness, ear pain, heightened sensitivity to sound (hyperacusis), or altered taste on the front two-thirds of the tongue—all pointing to broader facial nerve dysfunction.

Early recognition of these symptoms is essential. Prompt medical evaluation can help rule out serious conditions like stroke (which usually presents with central facial paralysis sparing the forehead) and initiate appropriate therapies such as corticosteroids, antivirals, eye protection, and physical rehabilitation.