Brief overview
- Symptoms: The symptoms depend on the particular form of leprosy. Possible symptoms include skin changes, loss of tactile sensation and paralysis.
- Prognosis: Leprosy is curable if it is treated correctly. However, if early treatment is not received, the disease may lead to progressive and permanent damage.
- Causes: Leprosy is caused by the bacterium Mycobacterium leprae.
- Risk factors: Leprosy is particularly prevalent in tropical and subtropical countries with high population density and low hygiene standards.
- Diagnosis: The diagnosis is made on the basis of the patient’s medical history, a physical examination and special examination methods to detect the pathogen.
- Treatment: Leprosy is treated with a combination of different antibiotics.
- Prevention: Appropriate basic hygiene and proper disposal of infectious materials must be observed in the treatment and care of leprosy patients.
What is leprosy?
Leprosy is a contagious bacterial disease, also known as Hansen’s disease or Hansen’s disease. It is caused by Mycobacterium leprae and occurs worldwide. The bacteria destroy the skin and mucous membranes and attack the nerve cells.
Countries particularly affected by leprosy include India, Brazil and Indonesia. Other countries affected include Nepal, the Republic of Congo, Mozambique and Tanzania.
In general, the number of cases in Africa, America, South-East Asia and the south-eastern Mediterranean has been falling since 2003. Nevertheless, leprosy still exists and every year thousands of people around the world contract the disease – many of them children.
For example, 202,256 new infections were reported to the World Health Organization (WHO) in 2019, including 14,893 children under the age of 14.
In Germany, however, only isolated cases of imported leprosy have been registered in recent years. In 2019, there was one reported case of leprosy. In 2018, however, no cases were reported to the competent authorities.
Leprosy in the Middle Ages
Leprosy was also very widespread in Europe in the Middle Ages. The disease was regarded as a “punishment from God”: the original name “leprosy” probably comes from the fact that people suffering from leprosy had to live (exposed) outside human settlements.
What are the symptoms of leprosy?
Doctors distinguish between the following forms of leprosy:
Leprosy indeterminata is a very mild form of the disease in which there are isolated, less pigmented (hypopigmented) skin spots. In 75 percent of cases, these heal spontaneously.
Tuberculoid leprosy or nerve leprosy is the milder form of the disease. Skin lesions occur only sporadically and are sharply defined. The areas are less pigmented (hypopigmented) or reddened and do not itch. In this form of the disease, the consequences of the nerve damage are in the foreground as typical leprosy symptoms.
The sensation of touch (temperature, touch and pain) is lost. As those affected do not feel pain early enough, they often injure themselves. The muscles atrophy, paralysis and sometimes severe deformities occur. The skin changes may heal on their own.
Lepromatous leprosy is a severe form of the infectious disease that occurs when the immune system is weak. Numerous tumor-like lumps appear on the skin, giving the face the appearance of a lion’s head (“facies leontina”).
The so-called borderline forms of leprosy are mixed forms that combine various symptoms of the other forms.
Is leprosy curable?
Leprosy is a chronic disease of the skin, mucous membranes and nerve cells. If diagnosed and treated in good time, the prognosis is favorable.
However, if left untreated, it can lead to progressive and permanent damage to the skin, eyes, limbs and nerves.
Damage that has already occurred, such as mutilation or paralysis, cannot be reversed. Around two to three million people worldwide are permanently affected by leprosy.
Leprosy: causes and risk factors
The cause of leprosy is the bacterium Mycobacterium leprae. The bacterium was discovered in 1873 by the Norwegian doctor Armauer Hansen as the cause of the infectious disease. Mycobacterium leprae is a less aggressive bacterium which, just like the tuberculosis pathogen, lives in the infected host cells.
As a result, the immune system only fights the pathogen directly with defense cells (“cellular defense”) and a defense reaction via antibodies (“humoral defense”) is almost non-existent. Only massive and prolonged exposure to the bacterium leads to leprosy.
Exactly how leprosy is transmitted has not yet been conclusively clarified. However, long-term, close contact with untreated leprosy patients appears to play an important role. Those infected excrete large quantities of the leprosy pathogen in their nasal secretions or via the skin ulcers that develop.
The bacteria are then presumably transmitted from person to person via small skin wounds or the respiratory tract as a droplet infection. Transmission of the pathogen to the unborn child during pregnancy is possible if the mother has leprosy.
Contrary to popular belief, leprosy is not a highly contagious disease! It is therefore not usually necessary to isolate people with leprosy.
Examinations and diagnosis
An institute for infectious diseases and tropical medicine is the right place to go if leprosy is suspected. The medical history (anamnesis) is very important for the diagnosis.
A decisive factor is whether the patient has spent time in leprosy risk areas in recent years, as leprosy has been eradicated in industrialized countries. During the physical examination, the doctor looks for typical skin changes, nerve changes and sensory disturbances.
Further examinations
Another method of diagnosis is the so-called molecular biological detection method, for example the detection of the genetic material of Mycobacterium leprae using a polymerase chain reaction (PCR). This makes it possible to diagnose leprosy at an early stage. The procedure also serves to confirm the diagnosis.
The lepromin test (Mitsuda reaction) is an antibody screening test that examines the body’s immune system. This test makes it possible to differentiate between tuberculoid and lepromatous leprosy.
Leprosy: Treatment
The treatment of leprosy depends on the number of pathogens. A combination of different antibiotics is used. In the case of tuberculoid leprosy, the active ingredients are usually dapsone and rifampicin, and in the case of lepromatous leprosy, clofazimine is also used.
The World Health Organization (WHO) recommends six months of therapy for so-called low-pathogen leprosy (). Pathogen-rich leprosy (), on the other hand, is treated over a period of at least twelve months with appropriate antibiotics.
In individual cases, treatment is continued for even longer. It may then be necessary to resort to substitute medication (“reserve leprostatics”).
Several years of treatment are often necessary to cure the leprosy completely. Supportive exercise therapy helps to prevent paralysis caused by leprosy.
Prevention
In order to prevent the transmission of Mycobacterium leprae, basic hygiene and the proper disposal of infectious materials (e.g. nasal and wound secretions) must be observed during the treatment and care of leprosy patients. For people who have come into contact with patients suffering from multibacillary leprosy, it is recommended that they be monitored for clinical symptoms for at least five years.
Accordingly, close contacts should be tested for infection every six months if possible. These testing intervals should be shortened if these people have additional risk factors such as immunodeficiency caused by medication or infections.
