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What are causes of numbness and tingling
Numbness and tingling is also called paresthesia, are abnormal sensations that can occur anywhere in your body, but they are often felt in your fingers, hands, feet, arms, or legs. Numbness and tingling sensation, which happens without warning, is usually painless and described as tingling or numbness, skin crawling, or itching.
Most people have experienced temporary paresthesia — a feeling of “pins and needles” — at some time in their lives when they have sat with legs crossed for too long, or fallen asleep with an arm crooked under their head. Numbness and tingling happens when sustained pressure is placed on a nerve. The feeling quickly goes away once the pressure is relieved. Don’t self-diagnose – see a doctor if you’re worried.
Chronic numbness and tingling is often a symptom of an underlying neurological disease or traumatic nerve damage. Numbness and tingling can be caused by disorders affecting the central nervous system, such as stroke and transient ischemic attacks (mini-strokes), multiple sclerosis, transverse myelitis, and encephalitis. A tumor or vascular lesion pressed up against the brain or spinal cord can also cause paresthesia. Nerve entrapment syndromes, such as carpal tunnel syndrome, can damage peripheral nerves and cause numbness and tingling accompanied by pain. Diagnostic evaluation is based on determining the underlying condition causing the numbness and tingling sensations. An individual’s medical history, physical examination, and laboratory tests are essential for the diagnosis. Your physicians may order additional tests depending on the suspected cause of the numbness and tingling.
There are many possible causes of numbness and tingling, including:
- Sitting or standing in the same position for a long time
- Injuring a nerve (a neck injury may cause you to feel numbness anywhere along your arm or hand, while a low back injury can cause numbness or tingling down the back of your leg)
- Pressure on the nerves of the spine, such as from a herniated disk
- Pressure on peripheral nerves from enlarged blood vessels, tumors, scar tissue, or infection
- Shingles or herpes zoster infection
- Lack of blood supply to an area, such as from hardening of the arteries, frostbite, or vessel inflammation
- Abnormal levels of calcium, potassium, or sodium in your body
- A lack of vitamin B12 or other vitamin
- Use of certain medicines
- Nerve damage due to lead, alcohol, or tobacco, or from chemotherapy drugs
- Radiation therapy
- Animal bites
- Insect, tick, mite, and spider bites
- Seafood toxins
- Congenital conditions that affect the nerves
Numbness and tingling can be caused by other medical conditions, including:
- Carpal tunnel syndrome (pressure on a nerve at the wrist)
- Diabetes
- Migraines
- Multiple sclerosis
- Seizures
- Stroke
- Transient ischemic attack (TIA), sometimes called a “mini-stroke”
- Underactive thyroid
- Raynaud phenomenon or Raynaud’s disease (narrowing of the blood vessels, usually in the hands and feet)
Table 1. Possible causes of numbness and tingling
| Symptoms | Possible condition |
|---|---|
| Pins and needles in fingers or toes that change color from white to red | Raynaud’s disease |
| Breathing too quickly, trembling hands, pins and needles | Hyperventilation |
| Pain and pins and needles that travels from your back, down your leg to your foot | Sciatica |
| Pins and needles in different parts of your body | Multiple sclerosis |
Long-lasting numbness and tingling may also be caused by:
- treatments – such as chemotherapy
- some medicines – such as HIV medication, medication to prevent seizures, or some antibiotics
- toxic substances – such as lead or radiation
- poor diet
- nerve damage – after an injury or illness
- drinking too much alcohol
Your health care provider should find and treat the cause of your numbness or tingling. Treating the condition may make the symptoms go away or stop them from getting worse. For example, if you have carpal tunnel syndrome or low back pain, your doctor may recommend certain exercises.
If you have diabetes, your doctor will discuss ways to control your blood sugar level.
Low levels of vitamins will be treated with vitamin supplements.
Medicines that cause numbness or tingling may need to be switched or changed. DO NOT change or stop taking any of your medicines or take large doses of any vitamins or supplements until you have talked with your doctor.
Because numbness can cause a decrease in feeling, you may be more likely to accidentally injure a numb hand or foot. Take care to protect the area from cuts, bumps, bruises, burns, or other injuries.
Go to a hospital or call your local emergency number if:
- You have weakness or are unable to move, along with numbness or tingling
- Numbness or tingling occur just after a head, neck, or back injury
- You cannot control the movement of an arm or a leg, or you have lost bladder or bowel control
- You are confused or have lost consciousness, even briefly
- You have slurred speech, a change in vision, difficulty walking, or weakness
See your doctor if:
- Numbness or tingling has no obvious cause (like a hand or foot “falling asleep”)
- You have pain in your neck, forearm, or fingers
- You are urinating more often
- Numbness or tingling is in your legs and gets worse when you walk
- You have a rash
- You have dizziness, muscle spasm, or other unusual symptoms
Numbness and tingling diagnosis
Your doctor will take a medical history and perform a physical examination, carefully checking your nervous system.
You will be asked about your symptoms. Questions may include when the problem began, its location, or if there’s anything that improves or worsens the symptoms.
Your doctor may also ask questions to determine your risk for stroke, thyroid disease, or diabetes, as well as questions about your work habits and medicines.
Blood tests that may be ordered include:
- Complete blood count (CBC)
- Electrolyte level (measurement of body chemicals and minerals) and liver function tests
- Thyroid function tests
- Measurement of vitamin levels
- Heavy metal or toxicology screening
- Sedimentation rate (ESR)
- C-reactive protein (CRP)
Imaging tests may include:
- Angiogram (a test that uses x-rays and a special dye to see inside the blood vessels)
- CT angiogram
- CT scan of the head
- CT scan of the spine
- MRI of the head
- MRI of the spine
- Ultrasound of neck vessels to determine your risk for TIA or stroke
- Vascular ultrasound
- X-ray of the affected area
Other tests that may be done include:
- Electromyography and nerve conduction studies to measure how your muscles respond to nerve stimulation
- Lumbar puncture (spinal tap) to rule out central nervous system disorders
- Cold stimulation test may be done to check for Raynaud phenomenon
Numbness and tingling treatment
The appropriate treatment for numbness and tingling depends on accurate diagnosis of the underlying cause.
