Last Updated March 2021 | This article was created by familydoctor.org editorial staff and reviewed by Deepak S. Patel, MD, FAAFP, FACSM

What is leprosy?

Leprosy is a chronic infection caused by Mycobacterium leprae (M. leprae) bacteria. It can affect the skin and the nerves of the hands and feet as well as the eyes and the lining of the nose. In some cases, leprosy can also affect other organs, such as the kidneys and testicles in men. If left untreated, leprosy can cause deformities of the hands and feet, blindness, and kidney failure.

Leprosy is also called Hansen’s disease.

Symptoms of leprosy

Leprosy progresses very slowly. Most people who have leprosy do not develop symptoms for at least a year after being infected by the bacteria. In most cases, it takes 5 to 7 years for symptoms to develop.

Leprosy damages the nerves and muscles. It may cause sores, lesions, lumps, and bumps to appear on the skin. There are 2 types of leprosy: tuberculoid leprosy and lepromatous leprosy. Tuberculoid leprosy is the less severe and less contagious form of the disease. Lepromatous leprosy is more severe and generalized. It is also more contagious. This type of leprosy may affect organs such as the kidneys, testicles (in men), eyes, and nose.

Depending on the type of leprosy, symptoms may include:

  • Skin sores or lesions that do not heal after several months (lesions are flat or slightly elevated and light in color or slightly red)
  • Skin lumps and bumps that can be disfiguring
  • Numbness of the skin because of damage to the nerves under the skin
  • Muscle weakness

What causes leprosy?

Doctors aren’t exactly sure how leprosy spreads. Leprosy is not very contagious. You can’t catch it by touching someone who has the disease. Most cases of leprosy are from repeated and long-term contact with someone who has the disease. Doctors believe that leprosy might be passed from person to person. This happens by breathing in droplets that get into the air when infected people cough or sneeze. Most people who come in contact with M. leprae do not develop leprosy. However, people whose immune systems are weakened from chronic disease (such as diabetesHIVAIDS, or heart disease) may be more likely to develop leprosy. This is because their immune systems are not strong enough to fight the bacteria.

Children are more likely to develop leprosy than adults.

How is leprosy diagnosed?

Your doctor will ask you questions about your medical history and the symptoms you are experiencing. They will probably want to remove a tiny piece of the affected skin (called a biopsy) to check for the M. leprae bacteria.

Can leprosy be prevented or avoided?

Even though the risk of catching leprosy is very low, you can still reduce your risk. The best way to prevent leprosy is to avoid contact with body fluids and the rashes of people who have leprosy.

Leprosy treatment

Leprosy is treated with antibiotics. Antibiotics can kill all the M. leprae bacteria in your body, but they can’t reverse nerve damage or deformities caused by leprosy. This is why early treatment is important. You may need to take antibiotics for 6 months or longer, depending on the severity of your infection.

Living with leprosy

If left untreated, leprosy can cause permanent damage to the nerves in the fingers, toes, hands, and feet. This may affect a person’s ability to feel pain and temperature in these areas of the body. When you can’t feel your fingers or toes, you may accidentally burn, cut, or hurt yourself. Repeated injuries and nerve damage can cause muscle weakness, deformities, and even the loss of fingers and toes. Untreated leprosy can also cause swelling, and skin sores and lesions that are more severe.

If leprosy damages the lining of the nose, it can cause frequent nosebleeds and constant stuffiness. If leprosy damages your eyes, it can lead to glaucoma and even blindness. Lepromatous leprosy can reduce the amount of the male hormone testosterone and sperm counts in men. This can lead to erectile dysfunction and infertility. In more severe cases, leprosy can also damage the kidneys, which can lead to kidney failure.

Questions to ask your doctor

  • What antibiotic is best for me?
  • Will the treatment cure my leprosy?
  • We caught the leprosy early, but will I have any complications later in my life?
  • Is there any way to heal the sores on my body?
  • Is there anything that can treat the numbness in my feet and hands?
  • Should I have regular eye exams, in case the leprosy has affected my eyes?
  • How often should I see my doctor?
  • How should I interact with my family while I have open sores?