Hypoaesthesia

Hypoaesthesia is a decreased sensitivity to touch that can make you feel strangely numb or insensitive in parts of your body. While often temporary and harmless, this reduced sensation can sometimes indicate a more serious underlying condition that requires medical attention.

Table of contents

• What Is Hypoaesthesia?
• How Hypoaesthesia Differs from Related Conditions
• What Causes Hypoaesthesia?
• Recognizing the Symptoms
• How Is Hypoaesthesia Diagnosed?
• Treatment Options

What Is Hypoaesthesia?

Hypoaesthesia, also spelled hypoesthesia, is the medical term for reduced sensation or decreased sensitivity to touch^[1]. This condition affects how you feel things on your skin, particularly tactile sensations (the sense of touch). When you have hypoaesthesia, you might notice that certain areas of your body don’t feel as much as they should when touched or that you can’t sense temperature or pain as well as before^[18].

The condition can be as mild as a slight decrease in feeling, or it can progress to a complete loss of sensation, which would then be called anesthesia^[1]. Hypoaesthesia can affect just one small area of your body, or it can spread to larger areas or multiple parts of your body at once^[1].

You may have experienced a temporary form of hypoaesthesia yourself. That strange tingling or numbness you feel in your limbs after sitting in an awkward position for too long, or finding an area of your skin oddly insensitive to touch, could be a brush with hypoaesthesia^[1].

How Hypoaesthesia Differs from Related Conditions

To understand hypoaesthesia better, it helps to know how it differs from other sensory changes you might experience.

Anesthesia represents a total loss of sensation, including touch, temperature, pain, and even the awareness of body position. In medical procedures, local anesthesia is intentionally induced to numb a specific area, preventing any pain sensation. In contrast, general anesthesia refers to medically induced unconsciousness used during surgery. However, anesthesia can also occur as a result of severe nerve damage or dysfunction^[1].

Paresthesia is a different type of abnormal sensation. While hypoaesthesia involves reduced feeling, paresthesia encompasses unusual sensations such as tingling, pricking (the “pins and needles” feeling), chilling, burning, or numbness. These feelings often occur in the hands, arms, legs, and feet, but they can happen anywhere in the body^[1]. Temporary paresthesia might occur due to pressure on a nerve, like when your leg “falls asleep,” but chronic paresthesia might indicate a more serious underlying condition.

What Causes Hypoaesthesia?

Hypoaesthesia can occur for many different reasons. The condition generally results from an injury or irritation of a nerve or group of nerves^[18].

Common causes include nerve compression, damage, or disease. Systemic medical conditions like diabetes can lead to hypoaesthesia, as can nutritional deficiencies^[1]. In the United Kingdom, diabetes (both type 1 and type 2) is the most common cause of peripheral neuropathy (nerve damage in the body’s extremities), which often presents with hypoaesthesia. Over time, the high blood sugar levels associated with diabetes can damage the nerves, a condition known as diabetic polyneuropathy^[3].

Physical injury to the nerves can also cause hypoaesthesia. This might happen through direct trauma from a blow or fall, compression that causes swelling, pressure on a nerve from repetitive movements or during surgery, or even from a tumor pressing on nerve tissue^[18].

In dentistry, hypoaesthesia can occur as a result of nerve damage during dental procedures. The most common cause is the injection of local anesthesia to numb an area being treated. In some cases, the needle may accidentally hit a nerve, causing temporary or permanent damage that leads to hypoaesthesia^[4]. Dental procedures such as tooth extractions, root canal treatment, or dental implant placement can also result in trauma to surrounding nerves, leading to nerve damage and hypoaesthesia. Prolonged pressure on nerves during dental procedures, such as keeping the mouth open for an extended period, may compress the nerves in the jaw and cause temporary or permanent nerve damage^[4].

Other causes include viral infections such as shingles, certain medications or excessive alcohol consumption, metabolic abnormalities, reduced blood flow to nerves, infections like HIV or Lyme disease, and hereditary nerve disorders^[18].

Recognizing the Symptoms

The main symptom of hypoaesthesia is a decreased ability to feel sensations in the affected area. You might experience a loss of feeling, also called numbness, or less ability to feel pain or temperature changes^[5].

When hypoaesthesia is caused by nerve damage, you may notice several related symptoms. These can include numbness or tingling in the affected area, a feeling of weakness, or even complete loss of sensation in severe cases. You may not feel the position of the numb part of your body, which can affect your balance and coordination^[18].

After dental work, hypoaesthesia symptoms depend on the severity and location of nerve damage. The most common symptom is a feeling of numbness or tingling in the lips, tongue, cheeks, or gums. This may be temporary or permanent. In some cases, hypoaesthesia may lead to a complete loss of sensation in the affected area, making it difficult to eat, drink, speak, or perform other daily activities^[4].

If the nerve damage is severe, it may lead to weakness or paralysis in the affected area, making it difficult to move the tongue, lips, or other parts of the mouth. Some people may experience pain or discomfort in the affected area, especially if the hypoaesthesia is caused by nerve inflammation or infection. Changes in taste may also occur, leading to a loss of taste or changes in the way food tastes^[4].

How Is Hypoaesthesia Diagnosed?

If you experience symptoms of hypoaesthesia, especially if they are new, constant, or cannot be explained by simple causes like sitting in an awkward position, you should see your doctor. It’s particularly important to seek medical attention if you experience early symptoms such as pain, tingling or loss of sensation in your feet, loss of balance or weakness, or a cut or ulcer on your foot that isn’t healing^[3].

A detailed history and thorough physical examination should be sufficient to identify the underlying cause of hypoaesthesia. Your doctor will ask about your symptoms and may perform tests to check the feeling in the affected area. They may also ask you to describe the pain and trace the numb or painful area^[3].

Routine laboratory tests should be ordered as part of the workup. Special laboratory, diagnostic, and imaging tests may need to be ordered to make a definitive diagnosis of the underlying cause. Changes related to certain nerve conditions may not appear on standard X-rays, but imaging of affected areas using CT scans or MRI might be ordered if your doctor suspects that a tumor could be causing your symptoms^[12].

Additional tests might include strength testing and reflex testing to help exclude other causes of your symptoms. Tests may also look for nerve root issues or damage to specific nerves. An electromyography (EMG) test measures electrical discharges produced in muscles to evaluate muscle and nerve conditions. A nerve conduction study uses patch-style electrodes placed on your skin to stimulate the nerve with a mild electrical impulse, helping diagnose damaged nerves^[12].

Generally, the sooner hypoaesthesia is diagnosed, the better the chance of limiting the damage and preventing further complications^[3].

Treatment Options

Treatment for hypoaesthesia depends on the underlying cause of the condition and the symptoms you’re experiencing. Not all underlying causes can be treated, but many can be managed effectively^[3].

If hypoaesthesia is caused by a specific, treatable condition, addressing that condition is the first priority. For example, if you have diabetes, gaining better control of your blood sugar level, stopping smoking, and cutting down on alcohol may help. This may improve the nerve damage or at least stop it from getting worse^[3].

Vitamin B12 deficiency, which can cause hypoaesthesia, can be treated with B12 injections or tablets. If hypoaesthesia is caused by a medication you’re taking, the condition may improve if the medicine is stopped^[13].

For nerve pain associated with hypoaesthesia, standard painkillers like paracetamol and ibuprofen often don’t work well. Instead, doctors may prescribe medicines specifically for neuropathic pain (pain caused by nerve damage). The main medicines recommended include amitriptyline (also used for treatment of headaches and depression), duloxetine (also used for treatment of bladder problems and depression), and pregabalin and gabapentin (also used to treat epilepsy, headaches, or anxiety)^[13].

These medications should usually be started at the minimum dose, with the dose gradually increased until you notice an effect. Higher doses may be better at managing pain but are also more likely to cause side effects. The most common side effects are tiredness, dizziness, or feeling “drunk.” These side effects should improve after a week or two as your body gets used to the medicine^[13].

If you have other symptoms associated with hypoaesthesia, these may need to be treated individually. For example, if you have muscle weakness, you may need physiotherapy to learn exercises to improve your muscle strength. You may also need to wear splints to support weak ankles or use walking aids to help you get around^[13].

When hypoaesthesia is caused by nerve damage during a dental procedure, treatment options may involve medications, physiotherapy, and seeking support from healthcare providers. If you experience hypoaesthesia after dental work, you should seek medical attention immediately so that appropriate steps can be taken to diagnose and treat the problem. Nerve damage left untreated may become permanent^[4].

The outlook for hypoaesthesia varies depending on the underlying cause and which nerves have been damaged. Some cases may improve with time if the underlying cause is treated, while in some people the damage may be permanent or may gradually worsen over time^[3].