A 10-year-old girl in Australia has been diagnosed with a rare neurological disorder that leaves her with excruciating pain in her right leg.

Bella Macey was diagnosed with complex regional pain syndrome (CRPS), a chronic disorder often dubbed the most painful condition known to mankind. Her condition was triggered by an infection on her right foot during a family vacation in Fiji.

CRPS has left Macey bedridden and she cannot engage in any of the daily activities without suffering the agonizing pain. "It's all sharp, it's burning, it's tingly, it's all sore. It's different pain [that] I never knew was possible. I can't have a shower, I can't have a bath...even with a tissue, you can't touch it with anything, otherwise I will scream," Macey said.

What is complex regional pain syndrome?

CRPS is a condition that causes chronic pain that typically develops after an injury, surgery, a stroke or a heart attack. The exact cause of the rare condition is not known. In most cases, CRPS occurs from nerve trauma or injury to the affected limb.

The symptoms of CRPS vary. Most often, the condition begins as throbbing pain, swelling, redness, changes in temperature and hypersensitivity in the arm, leg, hand or foot. In some people, signs and symptoms of CRPS may go away on their own. In others, the condition becomes irreversible once the color and texture of the skin, hair and nail changes, and patients suffer symptoms such as muscle spasms and tightening.

CRPS is a relatively rare condition that more commonly affects adults than children. Around 200,000 people suffer from the condition every year in the United States.

There are two types of CRPS:

  • Type I CRPS occurs without nerve damage after an illness or injury. It is also known as reflex sympathetic dystrophy.
  • Type II CRPS occurs after nerve damage. The condition is also known as causalgia.

Risk factors that increase the risk of CRPS

  • Poor nerve health: Certain health conditions such as diabetes and peripheral neuropathy and lifestyle habits such as smoking increase nerve damage and the risk of developing CRPS.
  • Immune system issues: Autoimmune diseases and people with other inflammatory diseases are at an increased risk of CRPS.
  • Genetics: Researchers believe that although rare, genes affect a person's ability to recover from an injury.