Tingling and numbness on the face, especially if it is one-sided, makes most of us think about a stroke. However, there are many possible causes of such symptoms. Understanding the nerves in this regions, the normal sensations and disturbances in it is therefore important to try to identify the exact cause of symptoms like tingling and numbness isolated to one part of the body.
Nerves of the Face and the Head
Any abnormality in sensation is usually a nerve problem. It is therefore important to understand which nerves are located in this region to further understand the type of conditions that can be responsible for tingling and numbness. There are two sets of nerves that cover the face and head (top and back). First is the trigeminal nerve that innervates the face and top of the head while the upper cervical nerves innervate the back of the head.
The trigeminal nerves (right and left) are cranial nerves meaning that it arises from the brain. It is the fifth cranial nerve (CN V). The trigeminal branch has three major branches, each of which supply different portions of the face and head.
- Opthalmic nerve is the first branch of the trigeminal nerve that lies just above the eye and covers the bridge of the nose, outer eye like the cornea and conjunctiva, upper eyelid, eyebrow, forehead and front half of the scalp.
- Maxillary nerve is the second branch that arises below the eye. It covers the upper lip, upper jaw, sides of the nose, a portion of the interior of the nose, the paranasal sinuses and most of the exterior of the nose.
- Manibular nerve has two branches, one of which innervates the lower jaw and the other that innervate the ear region and temples.
The cervical nerves arise from the spinal cord at different levels. The nerves responsible for abnormal sensations in the neck back of the ear and back of the head are cervical nerves 1 through 4 (C1 to C4). There is some degree of overlap but the first three (C1 to C3) supply the back of the head while the first four (C1 to C4) innervate the neck and ear region.
Causes of Tingling and Numbness
There are a number of reasons why tingling and numbness may occur. Sometimes it may be due to temporary acute injury like with an electric shock that disrupts the passage of impulses through the nerves. Recovery is usually quick. At other times the disturbance may be longer lasting like with compression, inflammation, infection, poor bloody supply and damage to a nerve. It is also possible that problem does not lie in the nerve but in the area of the brain or spinal cord where the nerve originates. Abnormalities in sensation are referred to as paresthesias.
Nerve injury may arise in a host of different ways. It may occur with mechanical, chemical or electromagnetic factors.
- Trauma to the nerve is usually associated with blunt or penetrating trauma to the face or head as is seen during an assault, motor vehicle accident, contact sports and with falls. Surgical trauma (iatrogenic) may arise with dental or head and neck surgery although it is often not intentional.
- Compression of a nerve is another common form of injury. It can arise when a mass forms and compresses the nerve as it passes through small foramens (holes) in the skull, when the intervertebral (IV) disc bulges or the vertebrae collapse on to the nerve emanating from the spinal cord (pinched nerve).
- Meningitis and encephalitis refers to inflammation of the lining around the brain and spinal cord, or inflammation of the brain tissue, respectively. Infections are the most common cause. It may be viral or bacterial in most cases and fungal infections can also be responsible although it is rare and mainly seen with a weakened immune system.
- Shingles (herpes zoster) is a nerve infection that arises when the chickenpox virus (varicella zoster) reactivates years or even decades after the initial infection. There is usually pain along the nerve pathway but tingling and numbness may also be present. It may lead to complications such as post-herpetic neuralgia which can last for years and is very resistant to treatment.
- Lyme disease is a less common infection caused by bacteria transmitted through tick bites. The bacterium Borrelia burgdorferi can cause a host of symptoms throughout the body and even lead to paralysis of the facial muscles. These effects of the bacterium may not arise immediately after the bit and in some cases may only present months or even years after the initial infection.
Non-infectious inflammation of the nerve may present in a number of different ways and the cause is not always known.
- Trigeminal neuralgia is a chronic condition that is believed to be due to inflammation of the trigeminal nerve for reasons unknown. It is more commonly seen in adults. Sometimes treatment of this condition can lead to complications such as anesthesia dolorosa or trigeminal deafferentation.
- Trigeminal neuropathy is a broad term to describe any type of trigeminal nerve problem. One type of neuropathic pain that can also present with numbness or tingling may be seen with injuries to the face or head, surgery, poorly managed diabetes or a stroke.
- Multiple sclerosis (MS) is an autoimmune nerve disease where the protective insulating layer of the nerve is damaged due to the action of the immune system. It may arise after certain viral infections but it is not caused by these infections. It is a chronic disease with occasional acute episodes.
Any disturbance in the blood flow to the nerve or brain can also lead to abnormal sensations (paresthesias) like tingling and numbness. The most significant of these circulatory conditions is a stroke where an interruption of the blood supply to the brain causes a portion of the brain tissue to die. This impairs the processing of incoming signals from nerves to the affected portion of the brain. Vasculitis which is inflammation of the blood vessels may also impact on nerve sensations and this is seen with certain types of vasculitis like giant cell arteritis.
- Guillain-Barre syndrome
- Syphilis complications
- Heavy metal toxicity
- Poisoning like with ciguatera and scombroid poisoning.
- Anxiety and panic attacks.
- Abscess (brain or spinal cord)
- Tumors (brain, face or spinal cord)
- Metabolic disorders like diabetes
- Medication such as anti-hypertensive drugs, certain antibiotics, antiretrovirals for HIV/AIDS, anesthetics and some antidepressants.
- Other substances including excessive alcohol consumption and illicit drugs.
- Nutritional deficiencies.