Facial numbness can be caused by a variety of factors. The most common cause of this symptom is interruption or compression of the facial nerves. Conditions that affect these nerves include stroke, trauma, and tumors. Numbness can also be experienced in the face due to medication side effects, neurological phenomena, and some medical conditions, such as diabetes and neuropathy.
The most common cause of facial numbness is a stroke. A stroke causes damage to the brain by depriving it of oxygen and blood. A stroke will often cause numbness in some part of the body, depending on which parts of the brain were affected by the lack of oxygen. If the nerves connected to the face are deprived of oxygen, full or partial facial paralysis will occur.
Nerve damage is another very common cause of facial numbness. The nerves are what tell the brain what sensations to experience and where. When the nerves are damaged, they can cause pain or a complete lack of sensation. Nerve damage can occur in several ways. Trauma from a blow to the head or neck can cause facial nerve damage severe enough to cause loss of sensation. Certain medical conditions like diabetes and neuropathy can also cause numbness in the face.
Occasionally, medication side effects can cause facial numbness. This is usually caused by medications that work to inhibit neurotransmitters in the brain. This side effect is not very common, but inhibiting neurotransmitters carries the risk of numbing the entire body or one or two parts of the body, including the face.
Facial numbness can also be caused by stress-induced neck tension. The nerves that give sensation to the face originate in the neck and shoulders. During stress, these muscles are some of the first to tense. Long periods of this type of tension can pinch these vessels and nerves, resulting in a loss of feeling in the face.
Facial numbness is also caused by migraines with aura. This particular type of migraine is considered a neurological phenomenon. Describes a migraine with symptoms that occur 10 to 30 minutes before the headache starts. One of these symptoms is numbness in the face. Numbness can also affect the tongue or extremities. Migraines with aura can also be experienced as visual hallucinations involving light, temporary blindness, and speech abnormalities.
Acoustic neuroma is another cause of facial numbness. It is a noncancerous tumor, also called vestibular schwannoma and neurolemmoma, that grows on the eighth cranial nerve. This nerve can sometimes press on the nerves that control facial sensation and movement, which are the trigeminal nerve and the facial nerves, respectively. If they press on any of these nerves, numbness in the face can occur.