Leprosy is a chronic infection caused by the bacteria, Mycobacterium leprae. It is also known as Hansen’s disease, after G.A. Hansen, who discovered the bacteria in 1873. There is a long history attached to this disease, dating to around 1550 BC, and recognized in records from ancient 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 this disease, which causes incurable disfigurement, physical disabilities, and psychological trauma.

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

Leprosy is classified by the type and number of skin areas affected. Types of leprosy include:

• Indeterminate leprosy (IL)

 

• Tuberculoid leprosy (TT)

 

• Borderline tuberculoid leprosy (BT)

 

• Borderline borderline leprosy (BB)

 

• Borderline lepromatous leprosy (BL)

 

• Lepromatous leprosy (LL)

The form of leprosy manifested depends on the immune system’s response to the infection. Indeterminate leprosy is the mildest form, and can be cured, or can progress to the next stage. Lepromatous leprosy is a severe and debilitating form that never reverts to a milder stage. It is also the only contagious form of the disease, when it is untreated.

Tuberculoid leprosy is a milder form and seen in patients with good immunity. In between TT and LL are borderline tuberculoid leprosy, borderline borderline leprosy, and borderline lepromatous leprosy.

When five or fewer skin areas are affected the leprosy is called paucibacillary. Skin samples from paucibacillary patients should not have any detectable bacteria. When six or more areas are affected, it is known as multibacillary leprosy, and most of the samples will show the presence of the bacterial organisms that cause leprosy.

There is a great deal of misinformation about leprosy.  For example, you cannot catch leprosy just by touching an infected person. While leprosy is not easy to catch, the mode of transmission is still uncertain.

There are certain factors that can increase the risk of contracting leprosy. The biggest risk factor is close- and long-term contact with an infected person or persons. Risk is increased for those who have compromised immune systems, and for people who live in certain countries. Eighty percent of the cases worldwide are from India, Indonesia, Myanmar, Brazil, or Nigeria. Almost all the cases seen in the United States are directly connected to immigrants from developing countries. 

Symptoms

The bacteria that cause leprosy multiply very slowly. This slow progress means it can take an average of five to seven years for symptoms to appear.

Flat discolored lesions characterize paucibacillary types, and similar symptoms are seen in TT leprosy.

Multibacillary types are characterized by:

• Symmetric skin lesions

 

• Nodules

 

• Plaques (broad raised areas)

 

• Thickened dermis

 

• Nasal congestion/ bleeding

All of these symptoms are seen at once in lepromatous leprosy.

To some extent, anyone infected with 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 disfigurement of the face can result. Eyes may be affected with glaucoma or blindness, kidneys may malfunction, and men may become infertile.

Diagnosis

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 may be performed to confirm diagnosis. The earlier a diagnosis is made, the better a patient’s chance of being cured.

Treatment

Antibiotics are used to treat leprosy. The World Health Organization (WHO) recommends multidrug therapy (MDT) with dapsone, rifampicin, and clofazimine. In multibacillary cases, MDT is given monthly for one year, while in paucibacillary cases rifampicin is given monthly and dapsone on a daily basis for a period of six months. People with only a single affected skin area are given a single dose of rifampin, ofloxacin and minocycline.

Antibiotics can kill the bacteria, but cannot reverse the nerve damage or deformities caused by leprosy. For severe lepromatous leprosy some doctors recommend lifelong treatment with dapsone.

Patient education is also important, with emphasis on taking the full course of medication. Patients should also be taught to deal with nerve damage, including how to protect numb limbs from injury.

Prevention

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

The WHO has made MDT freely available to most countries where leprosy is common, in hopes of eradicating the disease. The WHO also sponsors information campaigns to educate patients who are ostracized from their communities, because coming forward to receive treatment is critical.

Two major rehabilitation forms are physical and socio-economic. Physical rehabilitation programs provide physiotherapy, occupational therapy, and skills to help meet the physical demands of daily life. Socio-economic rehabilitation helps affected people rebuild their lives, reassuring families and communities about leprosy, and to help them live a fulfilling, dignified life.