lepra

Lepra, commonly known as leprosy, is a chronic infectious disease caused by the bacteria Mycobacterium leprae and, in some cases, Mycobacterium lepromatosis. It primarily affects the skin, peripheral nerves, mucous membranes of the nose and eyes, and can lead to permanent nerve damage and deformities if untreated.

Transmission occurs mainly through prolonged close contact via respiratory droplets from an untreated person. The infection is not highly contagious, and most exposed people do not develop the disease. Risk is higher in households of untreated patients and in areas with active transmission.

Clinical features vary by form. Tuberculoid (paucibacillary) disease presents with well-defined skin patches and sensory loss; lepromatous (multibacillary) disease shows widespread lesions, nodules, and diffuse nerve involvement. Borderline forms lie between these extremes. Nerve damage can cause numbness, weakness, muscle atrophy, and eye problems, contributing to disability if not treated promptly.

Diagnosis relies on clinical examination, skin smears or biopsies to detect acid-fast bacilli, and sometimes PCR. The Ridley–Jopling or WHO classification groups disease into paucibacillary versus multibacillary for treatment decisions.

Treatment is with multidrug therapy (MDT) recommended by the World Health Organization: paucibacillary disease typically treated for about 6 months; multibacillary disease for about 12 months, using a combination of dapsone, rifampicin, and clofazimine. Early treatment blocks transmission and prevents disability.

Prevention emphasizes early case detection and treatment; BCG vaccination provides partial protection. Public health efforts address stigma and aim to reduce long-term disabilities. The term lepra derives from historical language and reflects the disease’s characteristic skin involvement.