This is part of our House MD Project series.

Click here to read the connection to the episode (spoiler alert!)


On episode 13 of season 1, called cursed, a 12 year old boy named Gabe appears with a rash and pneumonia. After the team arrive at the conclusion he has anthrax and start treating him, skin lesions start appearing all over his body. Later on his arm gets paralyzed. After learning that the boy’s father has problems with the nerves in his hand and that he has been to India, House diagnoses Gabe with leprosy. (As you’ll learn ahead, leprosy doesn’t explain all of the symptoms the boy had. Once he was treated for leprosy (the treatment for anthrax works here too), his body caused a reaction which triggered the rest of the symptoms).

What is it?

Leprosy, also known as Hansen’s disease, is a chronic infectious disease caused by a bacteria. It affect the skin, eyes and nerves.

Who gets it?

That depends on where you’re from. Most cases of leprosy today happen in developing countries, mostly India and Brazil, although with travel it can happen anywhere.

In the US there are about 6,000 people with the disease, and about 95% of them got it abroad. About 200-300 new cases are reported each year, especially in states with large immigrant populations (such as California, New York and Florida).

Around the world about 2-3 million people are estimated to have the disease. About 86% of people with the disease live in one of 11 countries: Bangladesh, Brazil, China, Congo, Ethiopia, India, Indonesia, Nepal, Nigeria, Philippines, and Tanzania.

Leprosy around the world. Pink areas have the greatest amount of leprosy patients, followed by red, orange and yellow. In green areas the disease is rare.

There are a few risk factors – things that can put you at risk of getting infected:

1. Close contact – If you’re in contact with someone sick with leprosy.
2. Age – You’re more likely to get it if you’re older (and perhaps also if you’re between the ages 5-15).
3. Problems with the body’s defense systems – Most people will not develop the disease if they’re exposed to someone ill. Even if they do, they may develop a very mild form of the disease that heals by itself.
   Those who do develop the disease do so because a genetic defect in their body’s normal response, which should normally fight the bacteria.

What causes it?

Leprosy is caused by a germ called Mycobacterium leprae. It is spread by sick people through droplets from their nose and mouth, much like the common cold or the flu. Unlike them, though, it is not very contagious.

Mycobacterium leprae under a microscope. The germs are the red stuff scattered all over the picture.

Usually after we get infected with a germ, it takes time for it to grow, multiply and cause a disease. That time can take a few days with a cold. With leprosy, on the other hand, that time can be very long, and takes between 6 months and 40 years (!).

The leprae germ likes cool places in the body, so its best tourism sites are our superficial nerves, skin, the linings of the inside of our upper airways, the eyes, and the testicles. There they cause damage.

How does it feel?

Since, as mentioned above, it takes the bacteria a long time to multiply, the symptoms usually don’t appear before 1 year after infection (usually 5-7 years).

Skin – The disease causes characteristic rashes to appear. They can be a few flat, whitish areas which are numb to touch, in the milder form of the disease (called tuberculoid leprosy). In the more severe form of the disease (called lepromatous leprosy) there are many small bumps or large raised rashes of many sizes and shapes. There are also more areas of numbness and even weak muscles. It can also affect other areas in the body, such as our nose, kidneys, and testicles.

There can also be swellings and lumps on the skin.

Nerves – The sense of touch deteriorates so that the person can’t feel pain and temperature changes. These people may get burns or cuts and don’t notice it. This may lead to loss of toes or fingers. The damage to the nerves can also cause muscle deformation (causing things like clawed fingers).

These are the main symptoms, although there are more.

You can see some visuals of how this affects the body here. Be warned, though, that these aren’t easy pictures to look at.

How is it discovered?

The symptoms (such as the rash) give the doctor a clue. Doing a biopsy of infected skin (which means cutting a small sample and looking at it under a microscope) confirms the suspicion.

How is it treated?

Antibiotics are the treatment for leprosy. They can’t reverse the damage, but can stop any new damage from happening.

The leprosy bacteria are hard to kill and so treatment may continue for a long time – anywhere between 6 months of treatment to many years (and even a lifelong treatment in some cases).

What happens after treatment?

That depends on the type of disease (tuberculoid vs. lepromatous) – the more severe the form of the disease, the less chance there is for a cure. After cure, the disease may (rarely) return, which will require another treatment.

As we said above, leprosy isn’t very contagious. Only the lepromatous form of the disease, if untreated, is contagious (even then, not as much as other infections). Once treatment has begun, the disease is no longer contagious.

To avoid getting infected, avoid contact with bodily fluids and the rash of infected people. Sometimes the vaccine against tuberculosis may protect you against leprosy, but it’s not used very often.

What next?

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