Leprosy is a chronic infectious disease caused by a mycobacterium affecting especially the skin and peripheral nerves and characterised by the formation of nodules or macules that enlarge and spread accompanied by loss of sensation with eventual paralysis.
Leprosy infection ranges from the mildest indeterminate form to the most severe lepromatous type. Symptoms and physical findings vary depending on the stage of disease and level of infection. Symptoms of leprosy are generally so slight that the disease is not recognised until a cutaneous eruption is present. 90% of patients experience numbness first, sometimes years before the skin lesions appear. Temperature is the first sensation that is lost. Patients cannot sense extremes of hot or cold. The next sensation lost is light touch, then pain, and finally deep pressure. These losses are especially apparent in the hands and feet. A hypopigmented macule is often the first cutaneous lesion. From this stage, most lesions evolve into the lepromatous, tuberculoid or borderline types.
For the purpose of treatment, leprosy disease is separated into two categories:
The number of M. leprae in the body is small (less than 1 million) and a skin smear is negative. The patient is presented with fewer skin lesions. Most cases of leprosy is PB.
M. leprae can multiply in the body almost without any check and is thus present in high numbers. The bacillus has likely spread to almost all areas of skin and peripheral nerves. A skin smear test is positive and the patient presents more than five skin lesions.
A multidrug treatment regime is recommended for leprosy, because of the resistance to the primary drug used has become common in the past twenty years.
Dapsone is the primary drug indicated for the treatment of leprosy and it is almost always accompanied by at least one other medication. It works by preventing the formation of folic acid, thereby inhibiting the organism’s replication. Two of the most common additional drugs for leprosy treatment is Rifampin and Clofazimine. Rifampin is one of the main drugs used in tuberculosis and Clofazimine and is an antimicrobial that works by unknown mechanisms.
All three medications are taken orally and can be administrated on an out-patient basis. Dose and duration of these three medicines vary according to the stage of the disease and whether the patient is an adult or child. Multidrug regimens are recommended for 6 months (for Paucibacillary), to 2 years (Multibacillary).