Facial Droop – Causes of a Sagging Face

Facial droop is sagging of the face caused by loss of facial muscle tone. This is usually caused by an impairment of nerve function that supply the facial muscles, particularly involving the facial nerve. Most cases of facial droop are one-sided (unilateral) causing a distortion of the normal face structure. This typically appears like the lips are being pulled on one side and there may be difficulty in closing the eye or impairment of the taste sensation. A number of factors can contribute to a facial droop, including trauma, infections and other systemic diseases.

Facial Nerve

The facial nerve is one of the 12 cranial nerves that emerge directly from the brain. Marked as cranial nerve 7 (VII), the facial nerve exits the brain, giving off branches along its way to the parotid gland where it divides into five smaller nerves. The facial nerve is responsible for motor, sensory and parasympathetic functions of structures in the head.

Motor

• Facial muscles
• Stapedius muscle

Sensory

• Anterior two-thirds of the tongue

Parasympathetic

• Salivary and lachrymal glands

By controlling the facial muscles, the facial nerve allows us to change our facial expression, showing different emotions and assisting with talking and chewing to some degree. Its innervation of the stapedius muscle, a small muscle that stabilizes the stapes in the ear, allows it to control our perception of sound volume.

The facial nerve’s sensory functions in the anterior two-thirds of the tongue makes it responsible for the taste sensation in this area. The salivary glands and lacrimal (tear) glands are also partly controlled by the facial nerve, which can essentially ‘turn off’ these glands when necessary.

Causes of Facial Droop

Bell’s Palsy

Thi is one of the most common causes of a facial droop. Bell’s palsy is a temporary paralysis of the facial muscles caused by inflammation of the facial nerve, often due to a viral infection. It is usually a unilateral condition meaning that it only affects one side.

The herpes simplex virus, which causes cold sores and genital herpes, is most often involved. Diabetics, pregnant women and people with upper respiratory tract infections are more at risk of suffering from Bell’s palsy and the incidence increases with age.

Other Signs and Symptoms

• Sudden onset of facial paralysis or weakness involving one side of the face – facial droop.
• Difficulty with smiling or other facial expressions.
• Drooling.
• Difficulty in closing the eye on the affected side.
• Inability to wrinkle the forehead.
• Pain around or in the ear.
• Sounds seem louder on the affected side (hyperacusis).
• Hyperlacrimation or excessive watering of the eye on the affected side.
• Headache.
• Impaired taste sensation.

In most cases there is complete recovery within a few weeks or months even without treatment but some residual signs of facial paralysis may remain in some people where damage to the facial nerve is severe.

Ramsay Hunt Syndrome

This condition is caused by the infection of the facial nerve by the Varicella zoster virus, the virus which causes chickenpox. This virus may lie dormant for many years after a person suffers from chicken pox and but at some point may get reactivated and infect the facial nerve. Prompt diagnosis and treatment reduces the chance of complications. Ramsay Hunt Syndrome usually causes a unilateral facial droop.

Other Signs and Symptoms of Ramsay Hunt Syndrome

• Facial muscle weakness on one side of the face – facial droop.
• Painful red rash with vesicles (fluid-filled blisters) on the eardrum, external ear, area around the ear, palate or tongue.
• Loss of hearing.
• Ear pain (otalgia).
• Tinnitus or ringing in the ears.
• Difficulty in closing the eye.
• Dizziness or vertigo.
• Impaired taste sensation.

The risk of complications are reduced if Ramsay Hunt syndrome is diagnosed promptly and treatment initiated within a week.

Stroke or Cerebrovascular Accident (CVA)

A stroke occurs when blood supply to a part of the brain is disrupted due to any cause. This causes death of the brain cells by depriving them of oxygen. The symptoms depend upon the area of brain that is affected and the degree of brain tissue damage.

Signs and Symptoms of a Stroke

• Sudden numbness, tingling sensation, or weakness of the face, accompanied by similar symptoms in the arms and legs, generally on one side of the body.
• Loss of movement on one side of the body.
• Sudden confusion and difficulty in speaking or understanding.
• Drooling.
• Sudden visual disturbances in one or both eyes.
• Difficulty in walking or standing.
• Loss of balance, dizziness or vertigo.
• Severe headache with no apparent cause.

Facial droop caused by stroke may be differentiated from that due to Bell’s palsy by the following signs and symptoms.

1. The eye can be closed on the affected side in a stroke.
2. Wrinkling of the forehead is possible in a stroke.
3. Paralysis or weakness of muscles on one side of the body does not only affect the face in a stroke.

Facial Nerve Palsy

Facial nerve palsy is a nervous system disorder which occurs due to damage to the facial nerve, affecting movement of the facial muscles as well as sensation in the ears and taste sensation in the tongue. It is often caused by a tumor pressing on the nerve. Other causes may include HIV/AIDS, Lyme disease or sarcoidosis, but in some cases no cause can be identified.

Signs and symptoms of a Facial Nerve Palsy

• Drooping of the corner of the mouth.
• Drooping of the eyebrows.
• Facial asymmetry like one sided face swelling.
• Loss of forehead wrinkles and nasolabial folds (the deep folds which run from side of the nose to the corner of the mouth).
• Inability to close the eye.
• Excessive watering of the eye.
• Inability to keep the lips tightly closed. This may cause problems with keeping food in the mouth.
• Wasting or atrophy of the facial muscles in the later stages.

Tumors

Facial droop may occur from tumors arising from the facial nerve or from tumors which arise in the vicinity and secondarily affect the facial nerve. In a facial palsy caused by tumors, the signs and symptoms are more likely to be of gradual onset and there will be additional symptoms depending upon the type and site of the tumor. Headaches, seizures and hearing loss are more likely to occur.

A malignant parotid tumor is the most common tumor affecting the facial nerve and causing facial paralysis. Symptoms are gradual in onset and along with other features of facial palsy there will be a painful mass within the parotid gland. If treatment is delayed, the tumor can enter the brain via the adjacent nerves or may spread to the lungs (metastasis).

Benign and malignant tumors such as meningiomas, paragangliomas, chondrosarcomas, and chondromas may develop within the skull and affect the facial nerve. Each tumor will have its own particular manifestation as well as causing a facial droop.

Benign tumors, called schwannomas, arising from the facial nerve are not so common. If present, they may cause symptoms of facial twitching and facial muscle weakness.

Trauma

Trauma to the facial nerve may be caused by skull fractures, facial injuries or penetrating injury to middle ear. Severe head trauma can cause brain injury and thus affect the facial nerve fibers along its course in the brain and brain stem. Fracture of the temporal bone (the skull bone containing part of the ear canal, middle ear, and external ear) following physical trauma is a common cause of facial paralysis causing facial droop. In addition, there will be signs and symptoms such as hemotympanum (blood behind the tympanic membrane or ear drum), vertigo, deafness, or blood coming out of the external ear.

Surgery

Another form of trauma is iatrogenic injury which is caused by any form of surgery along the course of the facial nerve. This includes surgery of the parotid gland, acoustic neuroma resection, or tumor resection anywhere along the course of the facial nerve. Mastoid surgery, tonsillectomy, mandibular block anesthesia, or some dental procedures may also result in damage to the facial nerve and subsequent facial droop.

Damage may occur to the facial nerve during cervicofacial rhytidectomy (facelift operations or plastic surgery of the face). Facial drooping, as well as other signs and symptoms of facial palsy which occurs after injury or surgery, points to trauma being the cause of facial droop.

Facial Droop in the Newborn

Birth trauma

Facial droop can occur as a result of birth trauma during a difficult delivery, such as in forceps delivery or a ‘big’ baby.

Mobius syndrome

This is a rare condition where facial droop is present at birth. It is usually bilateral (on both sides) and occurs due to developmental deformities of the brain and the facial nerve. Other cranial nerves may be affected too.

Newborns with facial paralysis may have signs and symptoms such as :

• Facial droop.
• Asymmetric facial movements.
• Inability to close the eye completely.
• Problems with feeding.
• Presence of other congenital defects.

Lyme Disease

Infection with Borrelia burgdorferi via tick bites (deer ticks) results in Lyme disease, where facial droop is one of the features. The other associated signs and symptoms may be an expanding red rash, fever, general ill health, fatigue, muscle and joint stiffness, and headache. In later stages it can affect the heart and nervous system which can lead to heart failure or a facial nerve palsy.

Acute or Chronic Otitis Media

Otitis media is caused by an infection of the middle ear and this may lead to a facial palsy if the infection spreads to the facial nerve. Due to inflammation, there is compression of the nerve in its canal. There may be associated symptoms of discharge from the ears, ear pain and loss of hearing. Gradual onset of facial palsy may occur in a cholesteatoma, which is a cyst-like growth of skin in the middle ear which may develop as a result of chronic ear infection.

Sarcoidosis

Sarcoidosis occurs due to an abnormal reaction of the immune system. Granulomas or small lumps develop in certain organs of the body, such as lungs, lymph nodes, liver, brain, skin or other tissues. The cause of the disease is not known but tends to occur more frequently in persons of certain age and ethnicity. When granulomas develop in the brain, spinal cord or the facial nerve, symptoms of facial paralysis may occur.

Other Signs and Symptoms of Sarcoidosis

Depending on the organs involved the other symptoms may include :

• Fever
• Shortness of breath
• Cough
• Skin rash
• Enlarged lymph node
• Enlarged liver or spleen
• Seizures
• Bleeding from the nose
• Burning or itching of the eyes
• Discharge from the eyes
• Joint stiffness

Guillain-Barre Syndrome

In this rare disorder, the body’s immune system attacks part of the peripheral nervous system. It starts as weakness and numbness in the extremities and progresses rapidly to paralyze the whole body. It can develop into a medical emergency hence prompt diagnosis and treatment is essential. Facial paralysis with difficulty in eye and facial muscle movement may develop.

Diabetes Mellitus

Patients with diabetes are more likely to suffer from facial palsy such as Bell’s palsy.

Side Effects of Drugs

Certain medicines have been implicated in causing facial paralysis as a side effect.

• Tretinoin is a drug which is primarily used to treat acne but is also given to reduce skin damage caused by sun exposure. Facial paralysis has been reported as a rare side effect of this drug.
• Dofetilide is an anti-arrhythmic drug used to treat atrial fibrillation and atrial flutter. Facial paralysis may occur as an adverse side effect.

Bilateral Facial Droop

In most cases, a facial droop is unilateral (one-sided). However, a bilateral or facial droop affecting both sides is possible although uncommon. Bilateral facial paralysis is more likely to have some systemic pathology, such as :

• Lyme disease
• Guillain-Barre syndrome
• Sarcoidosis
• AIDS
• Leprosy
• Tuberculosis
• Poliomyelitis

References

1. Facial Nerve Paralysis. Medscape

Last updated on September 17, 2018.