leprosy

Last reviewed 11/2023

Leprosy is a chronic inflammatory disease which is caused by Mycobacterium leprae. It is characterised by a variety of clinical features, the best known of which is the peripheral nerve damage leading to chronic problems with loss of pain sensation resulting in unnoticed damage to tissues.

Multidrug treatment of leprosy since the early 1980s has had a profound effect on the prevalence and incidence of the condition worldwide. The number of patients declined from an estimated 12 million in 1985, to 2.4 million in 1995. However leprosy continues to be a challenge to health worldwide, with about 250,000 new cases being detected every year (1)

• Leprosy, also known as Hansen Disease, is a gradually progressive infectious disease caused by Mycobacterium leprae, an acid-fast obligate intracellular bacterium
  • is endemic in tropical and subtropical areas, with the highest prevalence in India, followed by Brazil
  • Leprosy has a broad spectrum of clinical presentations that are dependent on the host immune response, ranging from a single macular lesion to widespread nodules and plaques
    • also a spectrum from minimal involvement of the peripheral nervous system to significant hypoesthesia and other neurological deficits may be present
    • M. leprae has a predilection for cool areas of the body, explaining the tendency of leprosy lesions to occur on the extremities, nose, and ears

Iin countries where leprosy is non-endemic, diagnosis is frequently delayed and patients may present to multiple specialists before obtaining the correct diagnosis (2)

Reference:

• Rodrigues LC, Lockwood DN. Leprosy now: epidemiology, progress, challenges, and research gaps. Lancet Infect Dis. 2011 Jun;11(6):464-70.
• Lockwood DNJ, Reid AJC. The diagnosis of leprosy is delayed in the United Kingdom. Q J Med 2001;94:207-12