10. Lucio phenomenon

diffuse infiltration, which may develop into plaque and nodule formation. In addition, there may be nasal bleeding and edema on both legs. If the patient does not receive treatment, the pauci-bacillary form of leprosy can be downgraded to the multi-bacillary form (from tubercu-

A major problem in the management of leprosy patients is the occurrence of the leprosy reactions, which are consequences of the dynamic nature of the immune response to leprosy bacteria (M. leprae) that may occur before, during, or following the completion of multidrug therapy (MDT). Reactions in leprosy constitute the main complications of the disease, which can lead to serious consequences like nerve damage and deformities. Leprosy reaction is immunologically mediated episodes of acute or subacute inflammation, which interrupts the relatively uneventful usual chronic course of diseases affecting the skin, nerves, mucous membrane, and/or other sites. Reaction may occur in any type of leprosy expect the indeterminate type. Unless promptly and adequately treated, it can result in deformity and disability. Three types of reactions recognized are classified as: (1) type 1 reaction (T1R), (2) type 2 reaction (T2R) or erythema nodosum leprosum (ENL), and (3) the Lucio phenomenon [28]. Type 1 LR (T1R) and type 2 LR (T2R) are the main causes of nerve damage and permanent disability. The LR immune-pathogenesis is currently an important research focus, as it can

provide relevant targets and goals for early detection and control of this episode [29].

Type 1 reaction is associated with sudden alteration of cell-mediated immunity associated with a shift in the patient's position in the leprosy spectrum that is usually observed in borderline spectrum of the disease except very rare reports in lepromatous leprosy. If there is increase in the immunity, the shift is from borderline spectrum toward the tuberculoid pole and is called upgrading or reversal reaction. On the other hand, if there is sudden shift toward the lepromatous pole with reduction of immunity, it is called as downgrading reaction. These acute inflammatory events may accentuate the chronic course of the disease in the total clinical spectrum of the disease, usually in Borderline leprosy (BT, BB, and BL) and rare in LL. Clinical symptoms may present with complain of burning, stinging sensations in the skin lesions. They may have aches and pains in the extremities and loss of strength and/or sensory perception. Sign manifestations increased inflammation become erythematous swollen and may be tender looking like erysipelas, edema of extremities or face frequently accompanied by nerve involvement, rapid swelling with severe pain/tenderness (neuritis), and sometimes loss of nerve

Type 2 reaction is an immune complex syndrome (antigen–antibody reaction involvement complement). It is an example of type III hypersensitivity reaction by Coombs and Gell classification.

loid to lepromatous) through the borderline spectrum.

14 Current Topics in Tropical Emerging Diseases and Travel Medicine

9. Leprosy reactions

9.1. Type 1 reaction

function [28].

9.2. Type 2 reaction

Lucio phenomenon is a special type of reactions observed in uniformly diffuse shinny infiltrative nonnodular form of LL, which is chiefly encountered in Mexicans. Its unique feature is that it is seen only in untreated cases. The etio-pathogenesis is less well understood. M. leprae are found unusually in large numbers in the endothelial cells of superficial blood vessels, and this finding may be responsible for the serious vascular complications seen during the reactive phase. There is marked vasculitis and thrombosis of the superficial and deep vessel, resulting in hemorrhage and infarctions of the skin. Clinical manifestations begin with slightly indurated red-bluish plaques on the skin with an erythematous halo, sometimes larger inflamed bullous lesions, which burst leaving a deep ulcer with jagged edges. The lesion takes about 3 weeks to develop an ulcer from the initial lesion, and it heals slowly and secondary cellulitis may complicate. Patients remain afebrile [28].
