What Is Leprosy?
Leprosy is an infectious disease that causes severe, disfiguring skin sores and nerve damage in the arms, legs, and around your body. Leprosy has existed since ancient times.
But leprosy isn’t that contagious. You can catch it only if you come into close and repeated contact with nose and mouth droplets from someone with untreated leprosy. Children are more likely to get leprosy than adults.
Is leprosy still around?
It's rare, but people do still get the disease. About 208,000 people worldwide are infected with leprosy, most of them in Africa and Asia, according to the World Health Organization. About 100 people are diagnosed in the U.S. every year, mostly in the South, California, Hawaii, and some U.S. territories.
Leprosy mainly affects your skin and the nerves outside your brain and spinal cord, called the peripheral nerves. It may also strike your eyes and the thin tissue lining the inside of your nose.
The main symptom is disfiguring skin sores, lumps, or bumps that don’t go away after several weeks or months. The sores are flat and paler than the skin around them. Symptoms may also include:
- Skin that's stiff, thick, or dry
- Growths on the skin
- Lumps or swelling on your face or ears
Nerve damage can lead to:
- Loss of feeling in affected areas, which means you can't feel pain there and are at risk for injury
- Muscle weakness
- Vision problems
You could also have a stuffy nose or nosebleeds if the disease affects the mucous membranes in your nose.
Advanced leprosy symptoms
When the condition progresses, symptoms could include:
- Loss of eyebrows and/or eyelashes
- Sores on the soles of your feet that don't heal
- Pain, redness, and burning
- Deformities of the nose, hands, and feet
- Shorter toes and fingers
- Paralysis of your feet and hands
It usually takes about 3 to 5 years for symptoms to appear after you come into contact with the bacteria that causes leprosy. Some people don't develop symptoms until 20 years later. The time between contact with the bacteria and the appearance of symptoms is called the incubation period. Leprosy's long incubation period makes it very difficult for doctors to determine when and where a person with the disease got infected.
What Causes Leprosy?
Leprosy is caused by a slow-growing type of bacteria called Mycobacterium leprae (M. leprae). Leprosy is also known as Hansen's disease, after the scientist who discovered M. leprae in 1873.
Is leprosy contagious?
It's not clear exactly how leprosy is transmitted. When a person with the disease coughs or sneezes, they may spread droplets containing the M. leprae bacteria that another person breathes in. It takes close physical contact with an infected person to transmit leprosy. It's not spread by casual contact like shaking hands, hugging, or sitting next to someone on a bus or at a table during a meal.
Pregnant mothers with leprosy can’t pass it to their babies. It’s not spread by sexual contact, either.
Forms of Leprosy
Leprosy is defined by the number and type of skin sores you have. Specific symptoms and treatment depend on the type you have. The types are:
- Tuberculoid. A mild, less severe form. People with this type have only one or a few patches of flat, pale-colored skin (paucibacillary leprosy). The affected area of skin may feel numb because of nerve damage underneath. Tuberculoid leprosy is less contagious than other forms.
- Lepromatous. A more severe form of the disease. It brings widespread skin bumps and rashes (multibacillary leprosy), numbness, and muscle weakness. The nose, kidneys, and male reproductive organs may also be affected. It is more contagious than the tuberculoid type.
- Borderline. People with this type have symptoms of both the tuberculoid and lepromatous forms.
You may also hear doctors use this simpler classification:
- Single lesion paucibacillary (SLPB): One lesion (sore)
- Paucibacillary (PB): Two to five lesions
- Multibacillary (MB): Six or more lesions
If you have a skin sore that might be leprosy, the doctor will remove a small sample of it and send it to a lab to be examined. This is called a skin biopsy. Your doctor may also do a skin smear test. If you have paucibacillary leprosy, there won’t be any bacteria in the test results. If you have multibacillary leprosy, there will be.
You may need a lepromin skin test to see which type of leprosy you have. For this test, the doctor will inject a small amount of inactive leprosy-causing bacteria just underneath the skin of your forearm. They’ll check the spot where you got the shot 3 days later, and then again 28 days later, to see if you have a reaction. If you do have a reaction, you may have tuberculoid or borderline tuberculoid leprosy. People who don’t have leprosy or who have lepromatous leprosy won’t have a reaction to this test.
Treatment depends on the type you have. Antibiotics are used to treat the infection. Doctors recommend long-term treatment, usually for 6 months to a year. If you have serious leprosy, you may need to take antibiotics longer. Antibiotics can’t treat the nerve damage that can come with the disease.
Multidrug therapy (MDT) is a common treatment for leprosy that combines antibiotics. That means you’ll take two or more medications, often antibiotics:
- Paucibacillary leprosy: You’ll take two antibiotics, such as dapsone each day and rifampicin once a month.
- Multibacillary leprosy: You’ll take a daily dose of the antibiotic clofazimine in addition to the daily dapsone and monthly rifampicin. You’ll take multidrug therapy for 1-2 years, and then you’ll be cured.
You may also take anti-inflammatory drugs to control nerve pain and damage. This could include steroids like prednisone.
Doctors sometimes treat leprosy with thalidomide, a potent medication that suppresses your immune system. It helps treat the skin nodules. Thalidomide is also known to cause severe, life-threatening birth defects. Never take it if you’re pregnant or plan to become pregnant.
Is leprosy curable?
Leprosy can be cured. In the last 2 decades, 16 million people with the disease have been cured. The World Health Organization provides free treatment for all people with leprosy.
Without treatment, leprosy can permanently damage your skin, nerves, arms, legs, feet, and eyes.
Its complications can include:
- Blindness or glaucoma
- Hair loss
- Disfiguration of the face (including permanent swelling, bumps, and lumps)
- Erectile dysfunction and infertility in men
- Kidney failure
- Muscle weakness that leads to claw-like hands or not being able to flex your feet
- Permanent damage to the inside of your nose, which can lead to nosebleeds and a chronic stuffy nose
- Permanent damage to the nerves outside your brain and spinal cord, including those in the arms, legs, and feet
Nerve damage can lead to a dangerous loss of feeling. If you have leprosy-related nerve damage, you may not feel pain when you get cuts, burns, or other injuries on your hands, legs, or feet.
Early detection and treatment of leprosy is the best way to keep it from spreading.
While your risk for catching it is low, you can reduce the odds further by avoiding close contact with the skin and body fluids of people who have it. If someone in your household has had contact with a person with leprosy, see a doctor immediately. You'll need follow-up checks for at least 5 years.
Do armadillos carry leprosy?
Armadillos are mammals found in the southern U.S. Some carry the bacteria that causes leprosy. It's possible, but highly unlikely, that you could catch the disease from an armadillo. Because they can also carry other diseases, it's a good idea to avoid touching them.
Leprosy is an ancient disease that, while rare, still affects people today. But it's curable with antibiotics. If you think you may have been exposed to it, see a doctor right away.
Is leprosy a fatal disease?
You can't die from leprosy. But if left untreated, it can can cause complications that seriously harm your health. You may also end up with physical deformities that could lead to discrimination and stigma. But it's a myth that the disease can cause your toes, fingers, or other body parts to fall off.
How contagious is leprosy?
About 95% of people worldwide have natural immunity to the disease. And it's not very contagious -- you can't get it through casual contact with someone who has it. Experts think it spreads through the air when people who have it cough or sneeze. As soon as 1 day after you start treatment for leprosy, you're no longer contagious.