Lucio's phenomenon
Encyclopedia
Lucio's phenomenon is an unusual reaction seen almost exclusively in patients from the Caribbean
and Mexico
with diffuse, lepromatous leprosy
, especially in untreated cases. It is characterised by recurrent crops of large, sharply demarcated, ulcerative lesions, affecting mainly the lower extremities, but may generalise and become fatal as a result of secondary bacterial
infection
and sepsis
.
Lucio's phenomenon was first described by Lucio and Alvarado as a necrotizing skin reaction associated with non-nodular diffuse leprosy in 1852. This reaction was later named by Latapi and Zamora in 1948 as Lucio's phenomenon after identification of histopathological changes involving multiple, acute and necrotizing cutaneous vasculitis peculiar to pure and primitive diffuse leprosy (PPDL).
necrosis
of the epidermis and superficial dermis
, heavy infestation of endothelial cells
with acid-fast bacilli, and endothelial proliferation and thrombosis in the larger vessels of the deeper dermis.
, including antibiotics. In severe cases, exchange transfusion
is helpful.
and Mexico
, and rare in other parts of the world. Genetic and regional factors and factors specific to M. leprae have been shown to alter the manifestation of Lucio's phenomenon.
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
and Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
with diffuse, lepromatous leprosy
Leprosy
Leprosy or Hansen's disease is a chronic disease caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Named after physician Gerhard Armauer Hansen, leprosy is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions...
, especially in untreated cases. It is characterised by recurrent crops of large, sharply demarcated, ulcerative lesions, affecting mainly the lower extremities, but may generalise and become fatal as a result of secondary bacterial
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
and sepsis
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...
.
Lucio's phenomenon was first described by Lucio and Alvarado as a necrotizing skin reaction associated with non-nodular diffuse leprosy in 1852. This reaction was later named by Latapi and Zamora in 1948 as Lucio's phenomenon after identification of histopathological changes involving multiple, acute and necrotizing cutaneous vasculitis peculiar to pure and primitive diffuse leprosy (PPDL).
Pathogenesis
The mechanism of pathogenesis is thought to be mediated by immune-complex deposition.Morphology
Histologically, the lesions are characterised by ischemicIschemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
of the epidermis and superficial dermis
Dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...
, heavy infestation of endothelial cells
Endothelium
The endothelium is the thin layer of cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. These cells are called endothelial cells. Endothelial cells line the entire circulatory system, from the heart...
with acid-fast bacilli, and endothelial proliferation and thrombosis in the larger vessels of the deeper dermis.
Treatment
Lucio's phenomenon is treated by anti-leprosy therapy (dapsone, rifampin, and clofazimine), optimal wound care, and treatment for bacteremiaBacteremia
Bacteremia is the presence of bacteria in the blood. The blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal....
, including antibiotics. In severe cases, exchange transfusion
Exchange transfusion
An exchange transfusion is a medical treatment in which apheresis is used to remove one person's red blood cells or platelets and replace them with transfused blood products...
is helpful.
Epidemiology
Lucio's phenomenon is seen mainly in the CaribbeanCaribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
and Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, and rare in other parts of the world. Genetic and regional factors and factors specific to M. leprae have been shown to alter the manifestation of Lucio's phenomenon.