Overview of Leprosy

Leprosy is an infectious disease of the skin that is usually prevalent in tropical regions but is found also in other regions such as in the southern parts of america and in Hawaii.  It is caused by the bacterium mycobacteria leprae which is an acid fast bacilli that cannot be cultured in the laboratory. 

There are tweo types of leprosy.  These are: lepromatous leprosy and tuberculoid leprosy.  The way the infection spreads s through nasal drops.  Getting the disease depends on the status of the immune system of the affected individual.  People who have strong immune system or cellular immunity usually develop the less serious condition of tuberculoid leprosy. 

People with weak cellular immunity usually develop the more serious condition of the two, the lepromatous leprosy.  Put it in other words, tuberculoid leprosy happens in patients who develop T-cell hypersensitivity against the mycobacterium.  A test which measures the delayed hypersensitivity response to leprosy antigen is positive in this type of leprosy.

In lepromatous leprosy the same test for mycobacterium antigens is usually negative.  As far as skin is concerned so there are hypopigmentation of spots on the skin of affected individuals that can be mistaken for vitiligo.  In this type of leprosy these is nerve involvement in the form of nerve fibers thickening. 

Typical nerves which are usually affected  the ulnar nerve and the peroneal nerve in addition to the greater auricular nerve.  The skin in tuberculoid leprosy is characterized by the presence of granulomas which are usually manifestations of chronic inflammation.  Tuberculoid leprosy is less serious condition that the lepromatous leprosy.  It is slowly progressive even without treatment.  It usually cures completely with treatment. 

The other type of leprosy, the lepromatous leprosy usually occurs in people who have low cellular immunity.  The test that measures the delayed hypersensitivity response to leprosy antigens is usually negative.  Because there is no effective T-cell reaction the bacteria multipy undisturbed in the skin macrophages.  

Accumulation of macrophages in the skin causes thickening of the skin in addition to the presence of nodules in the skin.  In addition, to the skin the bacteria spread also through the blood stream causing infection of other parts of the body such as the eyes and the respiratory tract in addition to the testes. 

The preferred temperature for this bacterial growth is below 37 degrees celcius.  Therefore organs in the body at these temperatures are preferably attacked by the bacteria bacilli such as the testes and the respirastory tract and the eyes which usually can be at temperatures below 37. 

This type of leprosy is more serious than the tuberculoid type.  It can cause widespread destruction of body tissues.  Treatment to this type of leprosy is usually not satisfactory.  Tuberculoid leprosy can result in bone damage to the hands and foots due to possible trauma that can affect them due to the insensitivity of these parts of the body that is caused by nerve destruction. 

In this condition, ichthyosis and testicular atrophy in addition to leg ulcer are all seen in this type of leprosy.  Treatment to lepromatous leprosy is done with antibiotics such as rifampicin and dapsone and clofazimine.  These drugs are usually administered for a period of two years as a minimum to guarantee recovery.

Tuberculoid leprosy is treated with rifampicin and dapsone for a period of six monthes.  As was mentioned earlier lepromatous leprosy is the more serious condition among the two types of leprosy.  It takes longer time to cure.