Leprosy is a chronic, progressive bacterial infection caused by the bacterium Mycobacterium leprae. It primarily affects the nerves of the extremities, the skin, the lining of the nose, and the upper respiratory tract. Leprosy is also known as Hansen’s disease.

Hansen’s disease produces skin ulcers, nerve damage, and muscle weakness. If it isn’t treated, it can cause severe disfigurement and significant disability.

Hansen’s disease is one of the oldest diseases in recorded history. The first known written reference to Hansen’s disease is from around 600 B.C.

Hansen’s disease is common in many countries, especially those with tropical or subtropical climates. It’s not very common in the United States. The Centers for Disease Control and Prevention (CDC)Trusted Source reports that only 150 to 250 new cases are diagnosed in the United States each year.

What are the symptoms of Hansen’s disease?
The main symptoms of Hansen’s disease include: