LEPROSY

What is it?

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an acid-fast, rod-shaped bacillus. The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes, apart from some other structures.

Who gets it?

In 1995, there were an estimated 2 million cases in the world, most of them concentrated in South-East Asia, Africa and the Americas. Among them 1.3 million are registered for treatment of whom 1 million are treated with Multi Drug Therapy (MDT). The number of new cases detected worldwide each year is about half a million.

What are the symptoms?

In an endemic country or area, an individual should be regarded as having leprosy if he or she shows ONE of the following cardinal signs:

1. skin lesion consistent with leprosy and with definite sensory loss, with or without thickened nerves
2. positive skin smears

The skin lesion can be single or multiple, usually less pigmented than the surrounding normal skin. Sometimes the lesion is reddish or copper-coloured. A variety of skin lesions may be seen but macules (flat), papules (raised), or nodules are common. Sensory loss is a typical feature of leprosy. The skin lesion may show loss of sensation to pin pick and/or light touch. Thickened nerves, mainly peripheral nerve trunks constitute another feature of leprosy. A thickened nerve is often accompanied by other signs as a result of damage to the nerve. These may be loss of sensation in the skin and weakness of muscles supplied by the affected nerve. In the absence of these signs, nerve thickening by itself, without sensory loss and/or muscle weakness is often not a reliable sign of leprosy.

Positive skin smears: In a small proportion of cases, rod-shaped, red-stained leprosy bacilli, which are diagnostic of the disease, may be seen in the smears taken from the affected skin when examined under a microscope after appropriate staining.

A person presenting with skin lesions or with symptoms suggestive of nerve damage, in whom the cardinal signs are absent or doubtful should be called a `suspect case' in the absence of any immediately obvious alternate diagnosis . Such individuals should be told the basic facts of leprosy and advised to return to the centre if signs persist for more than six months or if at any time worsening is noticed. Suspect cases may be also sent to referral clinics with more facilities for diagnosis.

What tests will the Doctor want to do?

Diagnosis of leprosy is most commonly based on the clinical signs and symptoms.

What is the treatment?

The drugs used are a combination of rifampicin, clofazimine and dapsone for MB leprosy patients and rifampicin and dapsone for PB leprosy patients. Among these rifampicin is the most important antileprosy drug and therefore is included in the treatment of both types of leprosy.

Treatment of leprosy with only one antileprosy drug will always result in development of drug resistance to that drug. Treatment with dapsone or any other antileprosy drug used as monotherapy should be considered as unethical practice.