Paresthesia refers to a burning or prickling sensation that is usually felt in the hands, arms, legs, or feet, but can also occur in other parts of the body. The sensation, which happens without warning, is usually painless and described as tingling or numbness, skin crawling, or itching.

Most people have experienced temporary paresthesia—also known as a feeling of "pins and needles"—at some time in their lives when they have sat with their legs crossed for too long or fallen asleep with an arm positioned under their head. It happens when sustained pressure is placed on a nerve. The feeling quickly goes away once the pressure is relieved.

Chronic paresthesia is often a symptom of an underlying neurological disease or traumatic nerve damage. Paresthesia can be caused by disorders affecting the central nervous system, such as:

• Stroke and transient ischemic attacks (mini-strokes)
• Multiple sclerosis

• Transverse myelitis
• 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 paresthesia accompanied by pain.

What is limb numbness?

Numbness, sometimes called ‘paresthesia’, means you lose some or all sensation in the affected part of your body. You won’t feel a light touch, pain or temperature. Numbness is due to a problem with the nerves sending signals to the brain.

You can experience numbness anywhere in your body, but it’s most commonly felt in the fingers, hands, feet, arms, or legs. You might also feel a tingling, prickling, or ‘pins and needles’.

Having a numb limb can lead to other problems, such as falling or not noticing an injury, infection or sore.

What causes limb numbness?

There are many causes of limb numbness. Usually it’s just because you’ve been sitting on one of your legs or sleeping on an arm and this has compressed the nerves that go to the area.

Many more serious conditions can also make your limbs go numb. These include:

• an injury, such as a herniated disc, compressing or injuring a nerve (if it's in your neck it will affect your arm, if it's in your back it will affect your leg)
• diabetes
• chronic kidney disease
• stroke or a mini-stroke (numbness will be on one side)
• a tumour or abscess in the brain (numbness will be on one side)
• multiple sclerosis
• carpal tunnel syndrome
• fibromyalgia
• an insect bite
• migraine
• radiotherapy
• abnormal levels of some vitamins and minerals in your body, such as vitamin B-12, potassium, calcium or sodium
• pressure being put on a nerve, such as because of a tumour, scar tissue, enlarged blood vessels or an infection
• Raynaud's phenomenon
• seizures
• hardening of the arteries
• an underactive thyroid
• damage to the skin, such as from frostbite or shingles

Nerve damage can also be caused by some medicines, including chemotherapy medicines, as well as by too much alcohol or tobacco.

When should I see my doctor?

Seek emergency medical help by calling triple zero (000) for an ambulance if your limb is numb and you also suddenly have:

• weakness or paralysis
• confusion
• difficulty talking
• dizziness
• a sudden, severe headache

See your doctor if your limb is numb for a long time, if it's not caused by your posture, and if you have any other symptoms, including:

• dizziness
• muscle spasms
• a rash
• your leg numbness is worse when you walk
• you're urinating more often than usual
• you have had a recent injury, especially to your back, neck or head
• you're confused
• your speech is slurred
• you can't see properly
• you feel weak
• you're in pain
• you can't control your bowels or bladder

How is limb numbness treated?

Your doctor will order tests to find out the cause of your numbness. Make sure you tell them if you have had any recent injuries, illnesses or infections.

The treatment will depend on the underlying cause of the numbness. Long-term nerve problems can sometimes be treated with medicines including antidepressants, corticosteroids or gabapentin and pregabalin (if you have fibromyalgia, MS or diabetic neuropathy).

Can limb numbness be prevented?

You can massage the affected limb to help improve blood flow. Sometimes putting an ice pack or heat pack on the area for 15 minutes can help — but be very careful not to damage the skin. If the area is numb you won’t notice if it’s getting too hot or cold.

Exercise frequently to improve your blood flow and fitness. Make sure you get plenty of rest. Eat a healthy diet and avoid too much alcohol.

Some alternative therapies, such as massage or acupuncture, might also help. If your numbness is caused by a vitamin deficiency, your doctor may advise you to take supplements.

Diagnosis

Diagnosis is based on your medical history, physical examination, and laboratory as well as determining the underlying condition causing the paresthetic sensations. Your doctor may order additional tests depending on the suspected cause of the paresthesia.

Treatment

Treatment for paresthesia depends on accurate diagnosis of the underlying cause.

Treatment depends on the cause. For example, carpal tunnel syndrome may be treated with rest, splinting and medications such as anti-inflammatory and diuretic medications.

A compressed or irritated nerve may require treatment such as physiotherapy, medication or (in some cases) surgery to ease the pressure and allow full nerve functioning to resume.

Underlying conditions such as diabetes need to be properly controlled to ease associated symptoms, including pins and needles. The symptoms of nerve inflammation and damage caused by chronic overconsumption of alcohol generally improve once the person stops drinking.