Leprosy

Leprosy, also known as Hansen’s disease, is a chronic disease caused by the bacillus Mycobacterium leprae. It is transmitted via droplets from the nose and mouth during close and frequent contact with untreated cases, but is not highly infectious. Mycobacterium leprae multiplies very slowly with an incubation period of about five years, but symptoms can take as long as 20 years to appear. If left untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs and eyes.

Leprosy is curable, and treatment provided in the early stages averts disability. Early diagnosis and treatment with multidrug therapy (MDT) remain the key elements in eliminating the disease as a public health concern. Since 1995, WHO has made MDT available free of charge to all patients worldwide.

Symptoms may occur within 1 year but can also take as long as 20 years or even more to occur.

Clinical signs are easy to observe. Skin lesion has usually a different pigmentation than the surrounding normal skin (less pigmented, reddish or copper-coloured) and may have various aspects (flat, raised or nodules). Skin lesion can be single or multiple and may show a loss of sensation in the skin.

Skin smears are also used to diagnose leprosy.

Leprosy can be classified on the basis of clinical manifestations and skin smear results. In the classification based on skin smears, patients showing negative smears at all sites are said to have paucibacillary leprosy (PB), while those showing positive smears at any site are said to have multibacillary leprosy (MB).

Leprosy is curable with a combination of drugs known as multi-drug therapy (MDT), as the treatment of leprosy with only one antileprosy drug (monotherapy) will result in development of drug resistance to that drug. The combination of drugs used in the MDT depends on the classification of the disease (paucibacillary or multibacillary leprosy).

Since 1995, WHO has made MDT available free of charge to all patients worldwide.