Types Of Leprosy

Leprosy is a chronic granulomatous infectious disease caused by Mycobacterium leprae. It is an acid-fast bacillus, contracted in childhood but it manifests after a latent period of 2-5 years.

Poverty, poor hygiene and over crowding facilitate the spread of the disease. Nasal secretions are the main source of infection. It has a predilection for cooler parts of the body. Therefore, nasal mucosa and upper respiratory tract are chiefly affected whereas warmer areas like axilla and gluteal region are spared.

Main site of entry is skin and mucosa of upper respiratory tract. Leprosy affects the larynx in about 10% of the cases. The conjunctiva is much immune to leprous infection.

Typical lesions of leprosy include an anaesthetic patch of skin, thickened nerves, deformed leonine face and collapsed nose.

Types

Tuberculoid Leprosy

It occurs in patients with good cell mediated immunity with strong tissue response. Symptoms include localized, densely anaesthetic, hypopigmented, raised skin patch varying in size and number (few), with well-defined edge, early nerve damage and nerve thickening.

Neural involvement is early and the superficial nerves become palpable. When facial nerve is involved, it may lead to Keratitis and corneal ulcer leading to blindness.

Face and nose are not involved. The surface is dry. There is marked hyperaemia of the conjunctiva leading to diffuse catarrhal conjunctivitis. There is loss of normal skin organs such as sweat glands, hair follicles etc.

Lepromatous Leprosy

It occurs in patients with poor community with poor tissue response. The bacilli multiply fast causing widespread symmetrical development of the lesions in the skin and mucous membrane, which are numerous, small, widely distributed with shiny smooth surface and ill-defined margin, associated anaesthesia over lesions. Deformity rarely occurs. There is development of generalized, erythematous, multiple, macular rashes without nerve involvement.

In this type, the cutaneous lesions are more extensive. Involvement of face with loss of eyebrows and thickening of skin, gives rise to characteristic face called ‘Leonine Facies’. Nasal symptoms are common. Testes involvement may cause sterility.

Borderline Leprosy

It can be lepromatous or tuberculoid depending upon the tissue response.