What is leprosy?

Effects of Leprosy

The effects of leprosy are diverse and complex. The signs can differ remarkably and some of them are nearly identical to other diseases. That’s one of the reasons why diagnosis can be so difficult.

How leprosy is experienced depends on a few factors. Some of these factors include the type of leprosy bacterium the person gets, their immune response, how long they’ve had the disease, and their view of having leprosy, or the views held by their friends, family and broader community. Researchers are always investigating new factors that might affect people’s experiences and vulnerabilities to the disease. Medical researchers categorise the physical consequences of leprosy into different types. There are between two and eight of these types, depending on how you categorise them.

Skin patches, nerve damage and sensation-loss

Usually the first sign of leprosy is a patch (or patches) on the skin. They’re often paler than the skin tone or slightly red, and they tend to have hazy edges. But they can appear in other ways too. Sometimes they are shiny, copper-coloured nodules. On the affected area, the person might lose their sense of touch, their hair or be unable to sweat. People with some immunity to the bacterium can get these signs for a short period of time, until their body finishes fighting it off. Swollen nerves in the arm, leg and neck can also appear alongside these patches. Leprosy bacterium are the only bacterium known to invade nerves. When left untreated these swollen nerves can result in further complications. Sometimes the nerves have to be removed, and sometimes they impair the use of muscles and the ability to sense touch more widely. This is preventable if it’s caught early. It’s why early diagnosis and treatment is such a high priority.

Ulcers and deformity

Leprosy patches can’t always produce sweat which can cause dryness and cracking. This can result in wounds and infections, especially on the hands and feet. Small wounds can easily become infected during all activities of daily living and work—especially if you’re a labourer or farmer. Due to a loss of sensation, a person affected by leprosy doesn’t always notice their injuries nor take the necessary care to prevent further damage. This can necessitate amputation and permanent disability.

Damage to nerves can also result in a loss of power and paralysis of muscles. This can cause an inward curling of fingers and toes, and a drop to the wrist and foot. Leprosy can also affect the many muscles and nerves that protect and control a person’s eyes. This can result in blindness, and is especially frequent in advanced cases of leprosy. One researcher, M.D. Brand, said it’s an “irreversible double tragedy, since often such persons can neither see nor feel”. As a result, blindness has a massive impact on a person’s quality of life and their ability to keep an independent livelihood.

Severe cases of leprosy can also disfigure the face. This can give an alarming appearance—a thick hairless brow and larger ears, and a collapsed bridge of the nose. This can cause people to withdraw and people affected by leprosy to miss out on the support they need.


Among communicable diseases, leprosy remains a leading cause of disability. If leprosy is not treated in time, it can lead to ulcers, infections and amputations.

Early detection of leprosy is key, because it prevents lifelong impairments and stops ongoing transmission. Preventing impairments and disabilities can in turn reduce stigma and discrimination.


Leprosy affects people physically, but it can also destroy their psychological and social health. Stigma is a mark of disgrace. It happens whenever people categorise others according to something perceived as negative. When these negative attitudes aren’t challenged it can lead to prejudice and discrimination.

Stigma can cause a lot of problems for people affected by leprosy. To conceal their leprosy, people can avoid seeking medical help or other people. This can result in unemployment, comorbidities like depression, a worsening of their condition including permanent disability, which can intensify the stigma. It’s a tragic cycle.

Even when people affected by leprosy are cured, stigma can remain an obstacle to resuming regular life. People experiencing stigma may be unable to reintegrate into their families, marriages, jobs and wider communities. We’ve met countless people affected by leprosy who believe leprosy caused their spouses to seek divorce. In one study in Nepal, a third of leprosy patients were abandoned by their spouses. Community awareness, advocacy and counselling can help address stigma and are an integral part of tackling leprosy.

Download the FREE booklet “Leprosy What You Need To Know…”

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