Leprosy is a chronic infection caused by a bacteria Mycobacterium leprae. This is also known as Hansen’s disease after G.A. Hansen, who discovered the bacteria in 1873. There is a deep history attached to this disease, dating to around 1550BC, and recognized in the oldest civilizations of China, Egypt and India.

Leprosy has always been feared and misunderstood, causing significant stigma and isolation of those afflicted. Millions of people have suffered from the incurable disfigurement and physical disabilities, at the same time causing psychological trauma.

People were thus forced to live separately in settlements known as ‘leper colonies’. Most of these have been closed or developed into normal communities.

Clinical features

The infection primarily affects the skin, mucous membranes (nose), peripheral nerves (nerves outside the brain and spinal cord), eyes and testes (in males).

Leprosy is classified as per the type and number of skin areas affected. Types of leprosy based on severity include:

  • Indeterminate leprosy (IL)
  • Tuberculoid leprosy (TT)
  • Boderline tuberculoid leprosy (BT)
  • Boderline boderline leprosy (BB)
  • Lepromatous leprosy (LL)
  • Boderline lepromatous leprosy (BL)

These forms of leprosy manifested depend on the immune system response to the infection.

IL is the mildest form and can be cured or progress to the next stage.

LL is a severe and debilitating form that never reverts to a milder stage. c

TT is a milder form and seen in patients with good immunity.

In between, are BT, BB and BL forms that can result again depending on the cellular immunity of the patient.

As per the number of skin areas affected, leprosy is called paucibacillary, when five or lesser skin areas are affected. Skin samples from paucibacillary patients should not have any detectable bacteria.

When six or more areas are affected, it is known as multibacillary leprosy, where most of the samples will show the presence of bacterial organisms.

Risk factors

The mode of transmission of leprosy is still uncertain, but is understood to spread from person to person via respiratory droplets when infected people cough or sneeze. The disease is not contagious, but certain factors that increase the risk of contracting the disease include:

  • Close and long-term contact with the infected person
  • Compromised immune system (HIV/AIDS)
  • Countries endemic to the disease

The disease is seen more often in the age group of 5 to 15 years or over 30 years, and rarely seen in infants. Countries with warm and wet climate; tropics and subtropics have more cases.

Worldwide prevalence is around 5.5milion, with 80 percent of the cases from India, Indonesia, Myanmar, Brazil and Nigeria. Almost all the cases seen in the United States is a result of immigrants from developing countries.

The bacteria causing leprosy disease multiply very slowly, as a result the symptoms are not seen until a year after infection. Due to the slow progress of the disease, it can take an average of 5 to 7 years for signs to appear.

Paubacillary type is milder showing one or more hypopigmented skin macules (flat discolored lesions) and similar symptoms are seen in TT leprosy.

Multibacillary type shows symmetric skin lesions, nodules, plaques (broad raised areas), thickened dermis and nasal congestion and bleeding, all of which are seen in severe LL type of the disease.

To some extent, all forms of leprosy will show peripheral neurological damage, causing loss of sensation in the skin and muscle weakness.

In the long term, deformities (inward curving of the fingers, dropping of the foot) and disfiguring on the face can result.

Eyes may be affected with glaucoma or blindness, men may develop infertility and kidneys may malfunction.

Diagnosis of the disease is still based on the clinical signs and symptoms like localized skin lesions, sensory loss and peripheral nerve damage.

A skin biopsy to observe the bacteria microscopically may be done to confirm diagnosis. Earlier the diagnosis, better are the chances for cure.

A list of leprosy treatments are mentioned below:

  • Antibiotics are used to treat leprosy, and the World Health Organization (WHO) has recommended multidrug therapy (MDT) with dapsone, rifampicin and clofazimine regimen.
  • In multibacillary cases, MDT every month for one year is given, while in paucibacillary cases, rifampicin on a monthly basis and dapsone on a daily basis for a period of six months is the treatment choice.
  • People with only a singe affected skin area are given a single dose of rifampin, ofloxacin and minocycline.
  • The antibiotics can kill the bacteria, but cannot reverse the nerve damage or deformities caused by leprosy.
  • Dapsone being relatively inexpensive and safe to use, is recommended for lifelong treatment in lepromatous leprosy.
  • Patient education is also important, with emphasis on taking the full course of medication. Dealing with nerve damage and how to protect numb limbs from injury should be taught.

Overall, the risk of spread is low, and people on long-term medication become non-infectious. Only untreated lepromatous leprosy can be contagious. Preventive measures include avoiding contact with body fluids and rashes of infected people.

The WHO has made MDT freely available to most of the endemic countries, with an aim to reach elimination of the disease (less than 1 case/10,000 people).

Pockets of high endemicity still remain (Angola, Brazil, Central African Republic, Tanzania, republic of Congo, India, Madagascar, Mozambique and Nepal) and in such areas, information campaigns to educate patients who are ostracized from their communities, to come forward and receive treatment is very crucial.

Many people affected with the disease get rejected by society and it becomes the duty of the scientific and educated sections of the society to rehabilitate them and give them as normal a life as possible.

Two major rehabilitation forms are physical and socio-economic. Physical rehabilitation programs provide physiotherapy, occupational therapy, and aims to help meet the physical demands of daily life.

Socio-economic rehabilitation helps affected people rebuild their lives, reassuring families and communities about facts on leprosy, and to help them live a fulfilling life filled with dignity.