O Lucio's phenomenon is an uncommon type 2 reactional state occurring 
exclusively in patients with diffuse lepromatous leprosy (Lucio-Latapi leprosy). 
Previous case reports have been most frequent in Central America and rare in 
Asia and Africa. Lucio's phenomenon is characterized by necrotic ulcerations of 
the skin preferentially on the lower extremities usually in association with 
ongoing Lucio lepromatosis. The purpose of this report is to describe an unusual 
case of Lucio's phenomenon occurring four years after successful treatment of 
diffuse lepromatous leprosy. The patient was a 51-year-old man who had presented 
diffuse lepromatous leprosy ongoing since 1998. Diagnosis was documented based 
on histological and bacteriologic evidence. After successful treatment using 
dapsone (100 mg/d), rifadine (600 mg/month) and ethionamide (250 mg/d), the 
patient was lost from follow-up for 4 years. In January 2005, he consulted again 
for alteration of general status. Clinical examination showed inflammatory 
livedo on the lower extremities in association with several infiltrating 
maculo-papular lesions and painful erythemato-pupuric lesions on the legs and 
buttocks. The patient's skin was dry, shiny and galabrous with alopecia of the 
eyelashes and eyebrows. Examination of smear samples (skin and nasal) to 
identify mycobacterium leprae was negative. Histological study demonstrated 
epidermic necrosis with aspects of leucocytoclastic vasculitis. No Virchow cells 
were detected and Ziehl staining was negative. Search for circulating immune 
complexes and antiphospholipid antibodies was negative. Diagnosis of Lucio's 
phenomenon was made and the patient was treated using prednisone at a dose of 1 
mg/kg/d in association with rifampicine (600 mg/month) and dapsone (100 mg/d). 
Outcome was favorable after one month of treatment. Lucio's phenomenon has 
rarely been observed in Tunisia. To our knowledge this is the third case 
reported from Tunisia and only 13 cases have been reported in the world since 
1983. In all cases including the two from Tunisia, Lucio's phenomenon occurred 
during the course of treatment of ongoing Lucio-Latapi lepromatous leprosy (2). 
The remarkable features of our case are that Lucio's phenomenon occurred a long 
time after successful treatment of lepromatous leprosy and that the patient 
responded promptly to treatment. The pathogenesis of Lucio's phenomenon is often 
compared with that of erythema nodosum leprosum. Discussion focuses on 
pathophysiologic features and natural course of Lucio's phenomenon.