Leprosy

Leprosy, also known as Hansen's disease or Hansenitis, is an infectious disease known from antiquity, and historically carrying a great social stigma. It is now understood to be quite difficult to transmit, and can be managed and often cured with drugs available in developed countries, and increasingly worldwide.

The principal manifestations are dermatologic and periperhal neuropathy, but it can progress to systemic disease.

Etiology
It appears to have originated in India circa 700 BCE, moved to the Far East around 400 BCE, and to Europe in the fourth century CE, peaking in the fourteenth century. It spread from Europe to the Americas.

The pathogen had long been believed to be Mycobacterium leprae, but, in 2009, it was discovered that some cases are caused by the closely related Mycobacterium lepromatosis. The latter species causes the diffuse form of lepromatous leprosy found in Mexico and the Caribbean.

Diagnosis
Diagnosis, especially in the early stages, can be challenging because the signs and symptoms are subtle. Usually first manifesting as a skin disease, it produces hyposensitive areas. While there are few reasons to recommend cigarette smoking, patients often first sought medical attention when they smelled burning flesh, but felt no pain, when a cigarette, held between fingers, burned to a stub.