Congenital Insensitivity to Pain: What Is It?

Congenital insensitivity to pain carries the risk of suffering different injuries and not being aware of it. Let's see what this strange condition is all about.
Congenital Insensitivity to Pain: What Is It?

Written by Carmen Martín

Last update: 27 May, 2022

Pain is an unpleasant sensory experience, an alarm signal from our body to protect itself against something that’s causing it some kind of injury. While unpleasant, it’s one of the fundamental survival mechanisms of our species. And this is why congenital insensitivity to pain can be so dangerous.

Congenital insensitivity to pain is a rare hereditary disease. It is actually a group of diseases called hereditary sensory-autonomic neuropathies (HSAN). As the name of this group of diseases suggests, sufferers are unable to feel physical pain.

Until relatively recently this pathology was unknown. It was first described in 1932, which was a major breakthrough. Despite its low incidence, it’s a serious disease.

Not feeling pain means losing a great source of stimuli about what’s happening in our body. This means that people suffering from congenital insensitivity to pain are exposed to constant risk. In this article, we’ll tell you all about it.

What is congenital insensitivity to pain?

Congenital insensitivity to pain is actually a group of different diseases (hereditary sensory-autonomic neuropathies). Each of them is the result of the alteration of a particular gene whose function is related to pain sensation. The most relevant are:

  • HSAN type I. In this case, in addition to insensitivity to pain, there’s also a loss of thermal sensation. People who suffer from it usually have impaired hearing and touch. It appears around the age of 20.
  • Childhood or Type II. In this type, the alteration of touch is predominant, although insensitivity may be partial or complete.
  • Type III insensitivity. It usually occurs in newborns. Infants have difficulty suckling, low muscle tone, and are often irritable.
  • Type IV. This is the most common type. This type is associated with an inability to sweat – anhidrosis. Unlike the rest, touch is preserved and temperature changes are perceived. The biggest problem is that these individuals can’t regulate their body temperature, so many die of fever early.

All types carry the same risk, as insensitivity to pain prevents them from knowing the severity of any injury to the body. In fact, it’s even common for them to have wounds or other pathologies and not even know it.

For example, it’s quite common for these people to suffer fractures and not even realize it. Similarly, the skin is often quite characteristic, as they always have wounds, ulcers, or scars.

A digital representation of knee joint pain.
Insensitivity to pain can cause a person to be unaware of bone fractures.

How congenital insensitivity is diagnosed

As it’s a rare disease, the diagnosis isn’t easy. The most important thing is to carry out a good clinical history and proper physical examination. Especially in the case of infants, since it’s crucial to look for certain signs in them.

For example, many babies have sores on their tongue or lips. Insensitivity to pain often presents itself in wounds, bruises, or broken bones to which the patient shows no reaction.

In addition, doctors can perform certain complementary tests to help confirm the diagnosis. First of all, the electroneurogram is a test that specialists can use to assess whether the nerves are affected. They’ll also perform skin biopsies.

In the latter test, people with insensitivity usually have alterations in their nerve endings. In fact, those with HSAN type IV will also have alterations in their sweat glands.

However, one of the most important aspects is genetic testing, which is usually the confirmatory test. In addition, because it is an inheritable pathology, it’s important to ask about the patient’s family history.

A patient with a very bruised knee.
Patients with congenital insensitivity to pain have bruises, ulcers, and wounds on the skin.

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In conclusion

In conclusion, congenital insensitivity to pain is a group of different congenital disorders, all of which involve an altered gene related to pain sensation. Each type is accompanied by other symptoms such as:

  • Anhidrosis
  • Insensitivity to pressure
  • Insensitivity to temperature

This insensitivity poses a great risk to life, as pain allows us to locate lesions and know when something is wrong in our body. Therefore, it’s important to diagnose it as soon as possible and to raise awareness among these patients.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.