Leprosy is a chronic infection caused by the Mycobacterium Leprae which infects primarily the peripheral nerves and then the skin and some other tissues. The incubation period of the disease ranges from 2 to 7 years and it is transmitted through droplets of the rhino pharyngeal mucosa from bearers of lepromatous leprosy.
The Mycobacterium of leprosy has a particularity for the nervous tissue and for the peripheral nervous system in particular, where the first manifestation of the disease more frequently occurs. The disease is classified into four clinical forms. The criteria of classification are: clinical presentation, microbiological findings, lepromin reaction and histological presentation. It must be stressed that after the individual has been infected, the major role as to whether he/she will manifest the disease in the clinical form lies on the immune condition of the individual and particularly the cell immunity. Indeed, the condition of the cell immunity of the individual is what will define the type of leprosy. The clinical forms are: a) lepromatous leprosy b) intermediate c) tuberculoid and d) borderline.
It is the gravest and most contagious form of the disease. It develops straight from the beginning or is the result of the intermediate or other forms of the disease. The manifestations compile spots, papules, nodules, plaques or all the above.
It is the most benign form of the disease and it is not infectious. The only tissues that manifest clinical symptoms are the nerves and the skin. The skin damages are few and more than often solitary.
Intermediate leprosy lies between lepromatous and tuberculoid. Skin damages are intermediate in numbers between the two extreme types of leprosy, depending on the location of the individual on the spectrum of the intermediate. In regard of distribution, damages are asymmetric and may take the form of spots, plaques.
This primary and transient stage of leprosy may last for months or even years before it manifests itself in one of the previous forms and this is the reason why we should be skeptical in terms of prognosis. This form is characterized by spots while plaques or nodules never occur. The spots, sole or few in numbers, are slightly hypopigmented or reddish and may present slight aesthetic disorders