Facial droop refers to a sagging face that is caused by a loss of tone of the facial muscles. This condition should not be confused with the effects of aging that cause the facial skin to become loose. Facial droop is mainly caused by an impaired functioning of the nerves that supply the facial muscles.
Most cases of facial droop are caused by the dysfunction of the 7th cranial nerve, which is technically referred to as the facial nerve. After exiting the brain (at the level of the brainstem), the facial nerve gives out various branches on its way to the parotid salivary gland. The motor functions of the facial nerve are chiefly responsible for our facial expressions.
The motor fibers of the facial nerve innervate the facial muscles and the stapedius muscle. The facial nerve is also responsible for facial sensations. The anterior two-thirds of the tongue is innervated by the sensory fibers of the facial nerve. In addition, the facial nerve also supplies parasympathetic nerve fibers to the salivary and lachrymal glands.
Most cases of facial droop affect only one side of the face (termed as unilateral facial droop). This causes distortion of the normal face structure. For example, it may become difficult to close the eye on the affected side of the face. The eyebrow and the corner of the mouth on the affected side may droop. Taste sensations may also be affected.
Bilateral facial droop, although uncommon, may be caused by some systemic conditions. Examples of conditions that may cause bilateral facial droop include sarcoidosis, lyme disease, Guillain-Barre syndrome, AIDS, polio, tuberculosis, and leprosy.
Read more on tingling and numbness of the face.
Causes of Facial Droop
There are myriad causes of facial droop, including infections, trauma, and various systemic pathologies. Some of the common causes of facial droop have been discussed in detail.
Bell’s palsy refers to a temporary paralysis of the facial muscles that is caused by an inflammation of the facial nerve. The most common cause of facial nerve inflammation is a viral infection caused by Herpes simplex virus. Bell’s palsy is one of the most common causes of unilateral facial droop.
People with diabetes, infections of the upper respiratory tract, and pregnant women have a relatively higher risk of suffering from Bell’s palsy. The incidence of Bell’s palsy increases with aging. Most people recover from Bell’s palsy even without treatment. Recovery may take a few weeks to a few months. In cases where the damage to the facial nerve is particularly severe, some signs of facial paralysis may remain.
Read more on Bell’s Palsy.
Ramsay Hunt syndrome
Ramsay Hunt syndrome refers to a unilateral facial droop caused by an infection of the facial nerve by the Varicella zoster virus. Varicella zoster is the virus that is responsible for chickenpox. This virus can remain dormant in the body for many years. Upon reactivation, it can cause complications by infecting the facial nerve. Prompt diagnosis and treatment of this condition (within a week) can reduce the chances of complications.
Stroke is caused by reduced blood supply to any part of the brain. Oxygen deprivation caused by a lack of blood supply results in death of the brain tissue in the affected region. Facial droop caused by stroke has different features than facial droop caused by Bell’s palsy. For example, stroke can affect non-facial muscles in addition to the facial muscles. Also, the eye on the affected side of the face can still be closed in case of a stroke. Forehead wrinkling is also possible in case of a stroke.
Facial nerve palsy
Damage to facial nerve (often caused by a pressing tumor) can cause facial droop accompanied by loss of hearing and taste sensations. Other causes of facial nerve palsy include lyme disease, HIV/AIDS, and sarcoidosis. The cause of facial nerve palsy may not always be identifiable in every case.
Tumors affecting the facial nerve, either directly or indirectly, can also cause facial droop. In these cases, the signs and symptoms develop gradually. Examples of tumors that can affect the facial nerve include malignant parotid gland tumor, meningiomas, chondrosarcomas, paragangliomas and chondromas.
Trauma to the facial nerve due to a variety of reasons will also cause facial droop. Some examples include facial injuries, skull fractures, head trauma, penetrating injury to the middle ear and brain injury. One of the common causes of facial droop and facial paralysis is fracture of the temporal bone.
Surgery can also cause trauma to the facial nerve. Trauma is possible during surgery of the parotid gland, mastoid surgery, dental procedures, tumor removal from an area where the facial nerve is present, tonsillectomy and mandibular block anesthesia. Facelift operations can also cause injury to the facial nerve.
Sarcoidosis is characterized by the development of small lumps or granulomas in various organs of the body (such as liver, lymph nodes, lungs, skin, and brain). Abnormal immune reaction is thought to be involved in the development of these granulomas. Facial paralysis may occur when the granulomas affect the facial nerve.
Guillain-Barre syndrome is a rare autoimmune disorder in which the peripheral nervous system is attacked by the body’s immune system. This causes numbness and weakness in the extremities, and a progressive paralysis of the whole body. Facial paralysis is one of the features of this condition.
Facial droop can also occur as a side-effect of certain medications. Examples of drugs that can cause facial droop include tretinoin and dofetilide. Tretinoin is used for treating acne and severe skin damage caused by exposure to the sun. Facial droop is a rare side-effect of this drug. Dofetilide is used to treat atrial flutter and atrial fibrillation. Facial paralysis may occur as a side effect of this anti-arrhythmic drug.
Facial Droop in Children
Sometimes, facial droop may be present since birth. Congenital causes of facial droop include trauma caused by a difficult delivery and Mobius syndrome. Lyme disease caused by infection with Borrelia burgdorferi (transmitted via tick bites) can also cause facial nerve palsy in later stages of the disease. Infections of the middle ear (otitis media), which are a common occurrence in children, can also cause facial palsy if the facial nerve gets infected or inflamed.