May 28, 2017

Leprosy - Symptoms, Treatment and Key Facts

Leprosy was once feared as a highly contagious and devastating disease, but now it is established that it does not spread easily and treatment is very effective. However, if left untreated, the nerve damage it causes can result in crippling of hands and feet, paralysis, and blindness. Therefore, early diagnosis and treatment prevents disability related to the disease.

What is Hansen’s Disease?

Hansen’s disease (another name for leprosy) is a chronic infection caused by a slow-growing bacteria called Mycobacterium leprae, an acid-fast, rod-shaped bacillus. The bacteria may take up to 20 years to develop signs of the infection.

The disease can affect the skin, peripheral nerves, eyes, and lining of the nose (nasal mucosa). It attacks peripheral nerves, which become swollen under the skin causing the affected areas to lose the sense of touch and pain.

If left untreated, the nerve damage can result in paralysis of hands and feet. In very advanced cases, the person may have multiple injuries due to lack of sensation, and eventually the body may reabsorb the affected digits over time, resulting in the apparent loss of toes and fingers. Corneal ulcers and blindness can also occur if facial nerves are affected. Other signs of advanced Hansen’s disease include loss of eyebrows and saddle-nose deformity resulting from damage to the nasal septum.

Early diagnosis and treatment can cure the disease and usually prevents disability that can result from the disease, and people with Hansen’s disease can continue to work and lead an active life.

Brief history of the disease and treatment

Leprosy was recognized in the ancient civilizations of China, Egypt and India. Throughout history, people afflicted have often been ostracized by their communities and families.

Although leprosy was managed differently in the past, the first breakthrough occurred in the 1940s with the development of the drug dapsone. The duration of the treatment was many years, often a lifetime, making it difficult for patients to adhere to it. In the 1960s, M. leprae started to develop resistance to dapsone, the world’s only known anti-leprosy drug at that time. In the early 1960s, rifampicin and clofazimin were discovered and subsequently added to the treatment regimen, which was later labelled as multidrug therapy (MDT).

In 1981, a WHO Study Group recommended MDT. MDT consists of 2 or 3 drugs: dapsone and rifampicin for all patients, with clofazimin added for multibacillary disease. This drug combination kills the pathogen and cures the patient.

Since 1995, WHO has provided free MDT for all leprosy patients in the world, initially through the drug fund provided by The Nippon Foundation, and since 2000 through a donation agreement with Novartis. Elimination of leprosy as a public health problem (defined as prevalence of less than 1 case per 10,000 persons) was achieved globally in the year 2000. More than 16 million leprosy patients have been treated with MDT over the past 20 years.

Each year, however, about 150 to 250 people in the United States and 250,000 around the world get the illness. A number of countries in Africa, Asia and south America reported more than 1,000 new cases of Hansen’s disease to WHO between 2011 and 2015. For more, see overview of public health burden of Leprosy.


It is not known exactly how Hansen’s disease spreads between people. Scientists currently think it may happen when a person with Hansen’s disease coughs or sneezes, and a healthy person breathes in the droplets containing the bacteria. Prolonged, close contact with someone with untreated leprosy over many months is needed to catch the disease.

You cannot get leprosy from a casual contact with a person who has Hansen’s disease like:
  • Shaking hands or hugging
  • Sitting next to each other on the bus
  • Sitting together at a meal
Hansen’s disease is also not passed on from a mother to her unborn baby during pregnancy and it is also not spread through sexual contact.

Due to the slow-growing nature of the bacteria and the long time it takes to develop signs of the disease, it is often very difficult to find the source of infection.

Although there is evidence of natural infection of some armadillos found in southern United States with M.leprae, the risk of transmission to people is very low and most people who come into contact with armadillos are unlikely to get Hansen’s disease.

Overall, the risk of getting Hansen’s disease for any adult around the world is very low. This is because more than 95% of all people have natural immunity to the disease.

Signs and Symptoms

Symptoms mainly affect the skin, nerves, and mucous membranes (the soft, moist areas just inside the body’s openings). Usually, the affected skin changes color and either becomes: a). lighter or darker, often dry or flaky, with loss of feeling, or b). reddish due to inflammation of the skin.

The disease can cause skin symptoms such as:
  • Discolored patches of skin, usually flat, that may be numb and look faded (lighter than the skin around)
  • Growths (nodules) on the skin
  • Thick, stiff or dry skin
  • Painless ulcers on the soles of feet
  • Painless swelling or lumps on the face or earlobes
  • Loss of eyebrows or eyelashes
Symptoms caused by damage to the nerves are:
  • Numbness of affected areas of the skin
  • Muscle weakness or paralysis (especially in the hands and feet)
  • Enlarged nerves (especially those around the elbow and knee and in the sides of the neck)
  • Eye problems that may lead to blindness (when facial nerves are affected)
Symptoms caused by the disease in the mucous membranes are:
  • A stuffy nose
  • Nosebleeds
Since Hansen’s disease affects the nerves, loss of feeling or sensation can occur. When loss of sensation occurs, injuries such as burns may go unnoticed. Because you may not feel the pain that can warn you of harm to your body, take extra caution to ensure the affected parts of your body are not injured.

If left untreated, the signs of advanced leprosy can include:
  • Paralysis and crippling of hands and feet
  • Shortening of toes and fingers due to reabsorption
  • Chronic non-healing ulcers on the bottoms of the feet
  • Blindness
  • Loss of eyebrows
  • Nose disfigurement
Other complications that may sometimes occur are:
  • Painful or tender nerves
  • Redness and pain around the affected area
  • Burning sensation in the skin

Diagnosis and Treatment

Hansen’s disease can be recognized by appearance of patches of skin that may look lighter or darker than the normal skin. Sometimes the affected skin areas may be reddish. Loss of feeling in these skin patches is common. You may not feel a light touch or a prick with a needle.

To confirm the diagnosis, your doctor will take a sample of your skin or nerve (through a skin or nerve biopsy) to look for the bacteria under the microscope and may also do tests to rule out other skin diseases.

Hansen’s disease is treated with a combination of antibiotics i.e. MDT as already explained above. Typically, 2 or 3 antibiotics are used at the same time. Dapsone taken once daily and rifampicin taken once per month is for the paucibacillary form of the disease. Clofazimine is added for the multibacillary form. This strategy helps prevent the development of antibiotic resistance by the bacteria, which may otherwise occur due to length of the treatment.

Treatment usually lasts between one to two years, and the illness can be cured if treatment is completed as prescribed. Once treatment is started, the person is no longer contagious. However, it is very important to finish the entire course of treatment as directed by the doctor.

Although treatment will kill the bacteria, cure the disease and prevent it from getting worse, it does not reverse nerve damage or physical disfiguration that may have occurred before the diagnosis. Thus, it is very important that the disease be diagnosed as early as possible, before any permanent nerve damage occurs.

If you are treated for Hansen’s disease, it’s important to:
  • Tell your doctor if you experience numbness or a loss of feeling in certain parts of the body or in patches on the skin. This may be caused by nerve damage from the infection. If you have numbness and loss of feeling, take extra care to prevent injuries that may occur, like burns and cuts.
  • Take the antibiotics until your doctor says your treatment is complete. If you stop earlier, the bacteria may start growing again and you may get sick again.
  • Tell your doctor if the affected skin patches become red and painful, nerves become painful or swollen, or you develop a fever as these may be complications of Hansen’s disease that may require more intensive treatment with medicines that can reduce inflammation.

Key facts

  • Leprosy is a chronic disease caused by a slow multiplying bacillus, Mycobacterium leprae.
  • M. leprae multiplies slowly and the incubation period of the disease is about 5 years. Symptoms can take as long as 20 years to appear.
  • The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract, and also the eyes.
  • Leprosy is curable with multidrug therapy (MDT).
  • MDT treatment has been made available by WHO free of charge to all patients worldwide since 1995. It provides a simple yet highly effective cure for all types of leprosy.
  • Although not highly infectious, leprosy is transmitted via droplets, from the nose and mouth, during close and frequent contacts with untreated cases.
  • Untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs and eyes.
1). World Health Organization (WHO): Leprosy - Media centre. Accessed 16 September 2016. Available here:
2). Centers for Disease Control (CDC): Hansen's disease (Leprosy). Accessed 27 May 2017. Available here:

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