Leprosy is a chronic infection involving nerves and the skin. It is caused by a bacteria called Mycobacterium leprae.
What is going on in the body?
Leprosy occurs when thebacteria attacks tissues in the person's body. There are three forms of leprosy:
- lepromatous, the most serious type, which damages the upper respiratory tract, eyes, testes, nerves, and skin
- tuberculoid, which affects peripheral nerves and, sometimes, the surrounding skin, especially on the face, arms, legs, and buttocks
- borderline, which has characteristics of both lepromatous and tuberculoid leprosy
What are the causes and risks of the infection?
Leprosy is caused by the bacteria. It is spread through contact with nasal secretions from an untreated, infected person. Close contact over a period of time is needed to transmit leprosy. It is not highly contagious, but it can also be transmitted through skin breaks, such as one made with a contaminated needle.
Children are more susceptible than adults to contracting leprosy. Nine out of 10 people may have a natural immunity to the disease. Leprosy is most prevalent in underdeveloped regions, especially China and India. Worldwide, approximately 11 million people have the disease.
What can be done to prevent the infection?
Prevention involves avoiding close physical contact with a person who has untreated leprosy.
How is the infection diagnosed?
The diagnosis of leprosy begins with a medical history and physical examination. The characteristic skin lesions and loss of sensation allow the healthcare professional to diagnose the infection. Biopsies of skin lesions and peripheral nerves, and smears of skin or ulcerated mucous membranes, can help to confirm the diagnosis. Blood tests may be performed.
Long Term Effects
What are the long-term effects of the infection?
Leprosy damages nerves and causes a loss of sensation in the skin. The person can have repeated injuries without realizing it, since there is no perception of pain. The injuries can eventually result in ulcers, broken bones, and deformities. Nerve damage and physical disabilities can be permanent.
What are the risks to others?
Leprosy is contagious and can be spread to others through contact with nasal secretions from an untreated, infected person.
What are the treatments for the infection?
Antibiotics are used to treat leprosy. The World Health Organization, or WHO, has developed treatment guidelines that include a combination of antibiotics, including the following:
rifampin (i.e., Rifadin, Rimactane)
clofazlimine (i.e., Lamprene)
ethionamide (i.e., Trecator)
minocycline (i.e., Minocin, Solodyn)
clarithromycin (i.e., Biaxin)
- ofloxacin (i.e., Floxin)
In 1998, the Food and Drug Administration, or FDA, approved thalidomide (i.e., Thalomid) for the treatment of certain forms of leprosy. Since this medication can cause birth defects, there are strict guidelines for its use in women of childbearing age. Deformities such as wristdrop, footdrop, or clawhand may require surgery for correction.
What are the side effects of the treatments?
Antibiotics may cause stomach upset, diarrhea, and allergic reaction. Surgery may cause bleeding, infection, or allergic reaction to anesthesia.
What happens after treatment for the infection?
Antibiotic therapy must be continued for a long time because the bacteria that cause leprosy are difficult to destroy. Treatment may last from six months to many years. For those with deformities, a rehabilitation program involving physical therapy or occupational therapy can help maximize function.
How is the infection monitored?
A person with leprosy should be followed by his or her healthcare professional closely after treatment, since relapse does occur. Any new or worsening symptoms should be reported to the healthcare professional.
The Merck Manual of Medical Information, 1997
Professional Guide to Diseases, Sixth Edition. Springhouse: Springhouse Corporation, 1998