What is Hansen's Disease?

Hansen's Disease is another name for leprosy, a disease which has haunted human civilization for thousands of years. Many people prefer to use the term “Hansen's Disease” to refer to this condition because “leprosy” has many negative associations, many of which are undeserved. Historically, people with Hansen's Disease were isolated from society in leper colonies, shunned because people did not understand how the disease was transmitted, and because of widespread fear of physical disabilities. Because diagnostics was an imperfect science, people with syphilis and a range of other diseases were often isolated along with lepers, thanks to mistaken diagnoses of leprosy.

Clear evidence of leprosy has been uncovered in research dating to 600 BCE, and historical records suggests that the disease is much older. It is caused by an infection with Mycobacterium leprae. The bacteria colonizes the nervous system, especially in the extremities, and the mucous membranes. Classically, distinctive skin lesions known as granulomas appear in the extremities, and the patient often experiences a loss of feeling in the extremities as the bacteria attacks the body.

Contrary to popular belief, Hansen's Disease does not make the limbs fall off. However, people are more prone to extremity damage because of the loss of feeling, so they may lose fingers and toes to damage and infections which went unnoticed. Lepers are also not typically covered in rotting sores, but if they do get skin infections, the infections may not be identified immediately, again due to the loss of feeling; Hansen's Disease also impedes the sense of smell by attacking the membranes of the nose, so patients don't recognize the characteristic odors of infection and decay.

Hansen's Disease is named for Norwegian researcher Gerhard Henrik Armauer Hansen, who discovered the bacterium behind the disease in 1873. His discovery reshaped the way people thought about leprosy; previously, people thought the disease was used to punish the wicked, and that it was highly infectious. Later research uncovered the fact that around 95% of the population is actually naturally immune to Hansen's Disease, and that prolonged close personal contact with a patient who has an active form of the disease is required in order to be at risk of developing it.

Two forms of Hansen's Disease are recognized today: tuberculoid, a less serious form, and leprotomaus. Both can be treated with the assistance of antibiotics, although the sooner the treatment is administered, the better, because Hansen's Disease can cause permanent disability and damage. Hansen's Disease is primarily present in the tropics today, with treatment taking place in the community, rather than in isolated facilities.