Leprosy is a long-term, mildly contagious disease that mainly affects the skin, nerves, eyes, and the lining of the respiratory tract. It is now curable with a combination of antibiotics. Left untreated, it can cause permanent damage to the affected parts of the body.

Leprosy is caused by the bacteria Mycobacterium leprae, which is transmitted to other people via droplets from the nose and mouth of untreated individuals during close and prolonged periods of contact.

Patients with leprosy usually present with:

• Loss of feeling over one or more areas of the skin. The affected area is usually less pigmented than the surrounding normal skin or can also appear reddish or copper-colored.
• Loss of hair on the same areas with loss of feeling, or loss of eyebrows and eyelashes.
• Multiple bumps on the skin; bumps on the face may join together and give the face a deeply wrinkled appearance, resembling a lion.
• An enlarged, often palpable nerve with signs of damage such as loss of skin sensation and weakness of muscles in the surrounding areas.

Leprosy can usually be diagnosed based on the history and characteristic findings upon physical examination. To support the diagnosis, a positive slit-skin smear (a diagnostic tool that examines a skin sample under the microscope) can be done to visualize the bacteria in the skin. Some types of leprosy may not have enough bacteria to be confirmed through a skin smear, so a skin biopsy may be necessary.

Individuals with leprosy are treated using a multi-drug therapy (MDT) that lasts for 6–12 months. Different combinations of drug are given depending on the type of leprosy a person has. It is important that the treatment regimen be strictly followed to prevent development of drug resistance.

The best way to prevent catching leprosy is to avoid direct and prolonged contact with untreated patients (especially for young children). Other ways to reduce the risk of getting leprosy include practicing personal hygiene, and maintaining a healthy lifestyle through eating healthy food, having enough rest and exercise, and keeping a clean environment.

If someone becomes a close contact of an individual with leprosy, that person may be given an antibiotic called rifampicin, which has been shown to help prevent the development of leprosy.

While the BCG vaccine (which is primarily used against tuberculosis) may offer protection against leprosy, its efficacy is not consistent, making it not a cost-effective preventive measure.