leprosy

noun

lep·​ro·​sy ˈle-prə-sē 

1

: a chronic infectious disease caused by a mycobacterium (Mycobacterium leprae) affecting especially the skin and peripheral nerves and characterized by the formation of nodules or macules that enlarge and spread accompanied by loss of sensation with eventual paralysis, wasting of muscle, and production of deformities

called also Hansen's disease

2

: a morally or spiritually harmful influence

leprotic

le-ˈprä-tik 

adjective

Examples of leprosy in a Sentence

Recent Examples on the Web

Kelly, a Filipino American, grew up near Carville, La., where Joey was treated for leprosy. —Oc Register, 20 June 2025

In years past, many believed that the bacterium known as Mycobacterium leprae caused leprosy and that it was only spread in America by early European explorers and settlers. —Nick Butler, FOXNews.com, 5 June 2025

The BCG vaccine, while primarily for TB, can offer some protection against leprosy, particularly if someone in the household has leprosy. —Cindy Krischer Goodman, Sun Sentinel, 27 May 2025

In July 1998, the FDA approved thalidomide for the treatment of a painful complication of leprosy. —David Armstrong, CNN Money, 10 May 2025

Word History

Etymology

Middle English lepruse, from leprous

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing leprosy

• anti-leprosy

Kids Definition

leprosy

noun

lep·​ro·​sy ˈlep-rə-sē 

: a disease caused by a bacterium and marked by slow-growing spreading swellings accompanied by loss of sensation, wasting away of muscles, and by deformities

called also Hansen's disease

Medical Definition

leprosy

noun

lep·​ro·​sy ˈlep-rə-sē 

plural leprosies

: a chronic infectious disease that is caused by a mycobacterium (Mycobacterium leprae), affects especially the skin and peripheral nerves, and is characterized by the formation of nodules or macules that enlarge and spread and are accompanied by loss of sensation with eventual paralysis, wasting of muscle, and production of deformities

About 12 million people worldwide have leprosy, a disfiguring, chronic infection that damages nerves, skin, eyes, and mucous membranes.

—Harvard Health Letter

The good news is that leprosy is relatively easy to diagnose and cure. It is caused by the microbe Mycobacterium leprae, which produces telltale symptoms of enlarged nerves and light-coloured patches of numb skin on a patient's face or extremities.

—Bryn Nelson, New Scientist

Leprosy is actually the least infectious of the major communicable diseases.

—Sandra Dallas, Business Week

Leprosy … is progressive and causes the growth of widely distributed lumps on the skin and thickening of the skin and nerves. Severe cases are characterized by muscle weakness and paralysis.

—Insight

called also hansenosis, Hansen's disease, lepra

see lepromatous leprosy, tuberculoid leprosy