Leprosy: Symptoms, Types, Diagnosis, Prevention & Treatments

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Leprosy is a chronic contagious disease induced by the Mycobacterium leprae bacterium. The disease primarily affects the skin, exterior nerves, the nasal lining, the upper respiratory tract, and the eyes. Leprosy damages the nerves weakens the muscles and leads to skin sores in the body. It can lead to severe deformities and disabilities if not treated on time. This disease can trigger in early infancy and may even develop in adulthood.

Leprosy is among the primogenital diseases in history. References to this disease have been found from 600 B.C (as per the source from World Health Organization (WHO)).

Leprosy is also known by the name of Hansen’s disease. Leprosy is prevalent in various countries, mostly which have tropical or subtropical temperatures.

Types of Leprosy:

There are three different systems of classification of leprosy. According to the first system, leprosy is of two types: tuberculoid and lepromatous. Here, the immune response of a person to the disease defines what type of leprosy he/she has.

For example, in tuberculoid leprosy, a person exhibits good immune response with only a few skins sores on the body. This type of leprosy is considered mild and less contagious.

However, in lepromatous leprosy, the immune response is low and it causes extensive lesions and nodules on the skin and also affects the nerves and other vital organs of the body. This form of leprosy is severe and highly contagious.

WHO classifies leprosy based on the kind and number of affected skin regions. According to them, the first type of leprosy is paucibacillary. In this category, there are five or lesser sores without any bacteria found in the skin sample. In the second type of leprosy, which is called multibacillary, there are greater than five sores with bacteria found in the skin sample.

There is another system called the Ridley-Jopling system used by Clinical studies to classify leprosy depending on the type of symptoms. According to this system, there are six types of leprosy:

–  intermediate leprosy: is that form of the disease where only some lesions appear that may heal by themselves or turn into a more severe form.

–  tuberculoid leprosy: is a category in which few flat sores, some big and numb, with few lesions involving nerves are found; this form of leprosy may heal by itself, continue, or increase to a greater degree of severity.

–  borderline tuberculoid leprosy: in this from wounds are like tuberculoid though smaller in size and more in number; with less nerve involvement; this form may continue, change to tuberculoid, or progress to other forms of the disease.

–  mid-borderline leprosy: symptoms of this form are swollen lymph glands, rosy lesions with some numbness, which may reduce, continue, or advance to severe forms.

–  borderline lepromatous leprosy: numerous lesions, some of which are flat, raised wounds, plaques, and lumps, with numbness; symptoms may continue, retrogress, or progress.

–  lepromatous leprosy: in this form, numerous lesions develop with the presence of bacteria; the patient has hair loss, nerve impairment, limb numbness, disabilities, and the symptoms do not retreat.

Transmission of Leprosy:

The exact method of spread of leprosy is unknown. However, the common belief is that the disease is transmitted by human contact with an infected person.  Recent studies point out the respiratory tract as a possible route of transmission. There could be possibilities of the spread of the disease through insects too.

Leprosy is a highly contagious disease that spreads through the mucus of an infected person, usually when he/she sneezes or coughs. The bacterium that transmits the disease multiplies at a very slow rate. The incubation period i.e. the time between transmission and the onset of the first symptoms is like five years. The infected person may have the symptoms for as long as 20 years.


The cardinal signs of leprosy include:

– weakness in body muscles

– numb feeling in the hands, arms, legs, and feet

– skin abrasions

– thickened nerves causing nerve injuries

– painless ulcers

– eye damage

– hair loss (eyebrows)

– other deformities or disabilities of body organs

The skin sores become less sensitive to touch, pain, or temperature variations. They persist for many weeks and become lighter as compared to the normal skin tone.


Clinical diagnosis is through signs and symptoms like Hypopigmented patches of skin or red patches of skin with sensory loss or nerve damage or both.

Mostly, a skin biopsy or scraping is performed by a specialist. A small part of the skin is removed and sent to a lab for testing.

A lepromin skin test may also be performed to define the type of leprosy. For this, the doctor injects a small dose of leprosy-causing bacterium into the skin, usually in the upper arms. Patients with tuberculoid or borderline tuberculoid leprosy experience irritation with this injection.

There are other tests like CBC (complete blood count), creatinine test, LFT (liver function test), or a nerve biopsy that are conducted to see whether other body organs have been impacted.


Leprosy can be cured with multidrug therapy (MDT). Multidrug are used because treatment with just a single antileprosy drug also called monotherapy can lead to a person becoming resistant to that drug. Treatment of Leprosy can last for six months or up to a year. The kind of drugs combined to develop the MDT is largely dependent on the category or form the disease has taken. Rifampicin is the key antileprosy drug used in the treatment of both kinds of leprosy. For patients with multibacillary leprosy, it is recommended to use a combination of rifampicin, clofazimine, and dapsone (as per WHO rules); for those with paucibacillary leprosy, a mix of rifampicin and dapsone is used to make the MDT.

Doctors even prescribe more than one antibiotic at a time. They may also give you an anti-inflammatory medicine such as aspirin, prednisone, or thalidomide. Thalidomide is not recommended in pregnancy cases as it can lead to various birth defects.

Multidrug therapy (MDT) was first brought to notice by WHO in 1984. Soon it became the standard remedy for treating leprosy and WHO started supplying it free of cost to all countries prone to the disease.


Leprosy is a disease that grows very slowly and the symptoms may appear for 20 years. If detected in the early phase, there are minor complications. But if treatment is delayed or the disease is diagnosed late, the complications can become severe. Some of the major complications witnesses are:

– loss of sensation in extremities

– nervous impairment

– weakened muscles

– continued disfigurement (such as loss of eyebrows, disfigurement of the toes, fingers, and nose)

Risk Factors:

People living in endemic areas are at a higher risk of contracting the disease. The disease is widespread in various parts of India, Nepal, Japan, Egypt, China, and other areas across the world.

Those people who are in regular contact with infected persons for a sustained period of time have greater chances of getting the infection.

Some studies even provided evidence of the fact that genetic defects like region q25 on chromosome 6 may lead some people to have more possibilities of contracting the disease. Moreover, certain animals are known to carry the bacteria (such as sooty mangabey, armadillos, African chimpanzee, and cynomolgus macaque). People in contact with these animals are also at risk of being transmitted with the bacteria causing leprosy.


Myth #1: Leprosy does not exist anymore

Every two minutes, a person is diagnosed with leprosy. There are millions with the disease that are left undiagnosed every year. About two million people across the world have been already disabled by leprosy. The social stigma linked to the disease keeps people away from getting the right treatment, thus leading to life-term deformities in their body organs. Therefore, it is very important to do away with this prejudice associated if we want to end leprosy forever.

Myth #2: Leprosy cannot be cured

Leprosy is 100% curable through a multi-drug treatment, which involves a combination of two or more drugs.  Once treatment is started in an infected person, chances of spread of the infection become very less or is completely ruled out.

Myth #3: Leprosy may lead to loss of fingers, toes, and limbs

Leprosy does not lead to the loss of body organs. However, it can cause deformities or disabilities in the body organs due to nerve damage, especially in the areas like the face, hands, and feet. The nerve damage leads to sensory loss in these areas and sometimes, motor function or movement of limbs is compromised. A person may not be able to blink, move their hands and fingers or get hold of objects.
Small lesions may lead to ulcers and infection. This causes shortening of digits not falling off or completes loss.  With severe forms of leprosy, walking and moving abilities may also be crippled. When facial nerves are affected, it might lead to eye damage or blindness.

Myth #4: Leprosy affects the elder population

Since leprosy has a long incubation period, symptoms appear very late in life causing people to think so. Whereas the fact is that leprosy has no relation to age and recent cases that have come to light consist of 10% children.

Myth #5: Leprosy is the consequence of sins of past life or immoral character

This is just a superstition. Leprosy is caused by the bacterium Mycobacterium leprae.

Myth #6: A person infected with leprosy should be isolated

Not really. A person undergoing treatment will not transmit the disease as the bacterium is killed with antibiotic drugs and the infection is no longer contagious. Thus, the infected person under treatment does not need to be isolated from the rest.

Important Facts of Leprosy:

– Leprosy is a contagious disease that develops slowly and damages the skin and the nerves.

–  Leprosy is caused by the bacterium Mycobacterium leprae.

–  Early signs appear in skin extremities with loss of sensation.

–  Symptoms of leprosy are painless ulcers, skin sores, muscle weakness, and eye damage.

–  In later stages, ulcers grow large, fingers and toes are clawed, and facial disfigurement is seen.

–  The infection is transmitted via human mucus or nasal droplets.

–  Leprosy is rarely spread through animals like chimpanzees, armadillos, mangabey monkeys.

–  Some genetic abnormalities may also lead to leprosy in a person.

–  Antibiotics and Multi-drug Therapy are used to treat leprosy.

Frequently Asked Questions (FAQs):

1) Leprosy is an old disease, does it still exist?

Ans: Yes – about 200,000 plus new people are diagnosed with leprosy every year across the world. And there are 3 million people living with permanent disabilities due to leprosy.

2) Does leprosy cause claw hand and can it be treated?

Ans: Yes, leprosy may cause claw hands or toes. Since leprosy first damages the small nerves in the skin’s extremities, it spreads to other areas with large nerves like in the knee, elbow, wrist, and ankle when anti-leprotic drugs are not given on time. This further leads to sensory loss in the hands and feet. Muscles are paralyzed, causing clawed hands and toes.
It can be treated by reconstructive surgery that corrects the deformities in the hands and feet. The motor function can be restored through a muscle transfer technique. Physiotherapy also helps to strengthen the muscles.

3) Do fingers and toes disassociate from the body due to leprosy?

Ans: No. Due to nerve damage, there is the sensory loss in a person’s areas like hands and feet. Many a time, people injure themselves due to loss of sensation in their body parts leading to loss or shrinkage of tissues. Bones of fingers and toes become shortened, thus making them appear lost or removed.

4) How does leprosy spread?

Ans: Leprosy is mainly spread through contact with the nasal mucus of an infected person, either while sneezing or coughing. A person with close and persistent contact with an infected person who is not being treated with MDT can acquire the disease.

5) Is leprosy highly infectious?

Ans: Around 95% of the world population is naturally immune to the disease. The chances and rate of infection are very less due to the same fact.

6) What if a pregnant women catches leprosy?

Ans: It has been observed that women with leprosy deliver normal babies and the disease is not found to be transmitted from the mother to the baby. Pregnant mothers with leprosy are given MDT thereby nulling any chances of transferring the disease to their babies.


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