Leprosy

Leprosy is an infectious pathology, also known as Hansen’s Disease. It is caused by Mycobacterium leprae and affects the epidermis, mucosa (oral and respiratory) and the nervous system. The most common method of transmission is by direct contagion from person to person. Notwithstanding that its incidence has markedly decreased in recent decades, it is still a public health issue in many parts of the world (e.g. Brazil, India, Indonesia, Myanmar (Burma), Nigeria and other African states).
Historically, two clinical variants have been recognised: tuberculoid leprosy and lepromatous leprosy. The occurrence of either depends on the host’s cell-mediated response: tuberculoid leprosy is present in patients with an elevated immune reaction whilst lepromatous leprosy occurs in patients with a lowered cell-mediated response. Tuberculoid leprosy is characterised by the appearance of hypo-pigmented patches which occur mainly on the skin, being asymmetrical and associated with a loss in sensitivity. The trigeminal and facial cranial nerves are the most affected.
On the other hand, lepromatous leprosy is more widespread and more easily involves the mucosa. It is characterised by numerous, well-defined, hypo-pigmented macules or papules which affect the skin bilaterally and in a symmetrical way; they can over time demonstrate an infiltrative potential. Alopecia is often present with the destruction of the sebaceous and sweat glands. The face is typically affected by a loss of hair, eyelashes and eyebrows (thereby causing the so-called leonine facies), epistaxis, nasal congestion and a loss of smell. Another pathognomonic sign is a collapse of the nasal pyramid, involving the septum and nose floor.