Authors: Dr Elise Ouedraogo, Dermatology Registrar, University Paris VI, Paris, France, Prof Pierre Couppie, Dermatologist, University Antilles-Guyane, French Guiana. DermNet NZ Editor in Chief, A/Prof Amanda Oakley, Dermatologist, Waikato Hospital, Hamilton, New Zealand. March 2017
Leprosy is a bacterial infectious disease that mainly affects people in developing countries, including Brazil, Bangladesh, India, Democratic Republic of Congo and Nigeria.
The type 1 lepra reaction is a delayed type of hypersensitivity to M leprae antigens. It is also called a lepra 1 reaction.
The lepra 1 reaction is unpredictable. It occurs in patients with borderline disease, ie, the transition between tuberculoid leprosy (TTL) and lepromatous lepromatous leprosy (LLL).
The classification of borderline leprosy includes:
Type 1 lepra reactions typically affect skin and nerves, and there are no systemic symptoms. The reaction is classified as mild or severe.
A mild type 1 lepra reaction is characterised by few inflamed plaques and no nerve impairment. A severe type 1 lepra reaction is characterised by many inflamed plaques and nerve impairment.
A type 1 lepra reaction is clinically suspected in a patient with borderline leprosy that develops symptoms within a few months of starting treatment.
There are no routine laboratory tests. Skin biopsy may reveal:
There is no increase of polymorphonuclear neutrophils in blood count or change in C-reactive protein (CRP) levels. Type 1 lepra reactions have been associated with elevated level of serum chemokine 10.
A mild lepra 1 reaction requires supportive care.
A severe lepra 1 reaction with nerve impairment requires prompt treatment.
The natural course of an untreated type 1 lepra reaction is for it to persist for several months.
A type 2 lepra reaction is characterised by an acute immune complex vasculitis affecting the skin and other organs. It is also called lepra 2 reaction, and is poorly understood. It is also called erythema nodosum leprosum.
The type 2 lepra reaction occurs in patients with:
Lepra 2 is commonly associated with:
The clinical features of lepra 2 reactions depend on severity and which organs are affected.
A type 2 lepra reaction is clinically suspected if a patient with lepromatous lepromatous or borderline lepromatous leprosy complains of fever and fatigue and has multiple painful red skin nodules, whether or not they have received treatment.
Blood tests show high inflammatory markers.
Pathology is essential to confirm type 2 lepra reaction. A biopsy of a new red nodule less than 24 hours old shows:
Treatment depends on severity, assessed clinically and supported by laboratory tests. A mild cutaneous reaction without other organ impairment can be managed by supportive care:
Treatment for severe lepra 2 reactions may include:
Without treatment, lepra 2 reactions continue for about 2 weeks then settle down. Recurrences are frequent.
Untreated type 2 lepra reactions can result in renal failure requiring dialysis, liver failure requiring transplantation, blindness, and/or long-term inflammation of the testicles.
Lucio phenomenon is a very rare, acute and severe complication of longstanding and untreated lepromatous lepromatous leprosy. It may be life threatening.
Lucio phenomenon is treated intensively with systemic steroids.
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