Acute exudative arthritis in leprosy--rheumatoid-arthritis-like syndrome in association with erythema nodosum leprosum.

Erythemi'nodosum leprosum is a fairly common complication of lepromatous leprosy and is variously reported to occur in 30 to 40% of all patients with lepromatous leprosy on sulphone treatment (Buu Hoi and Basset, 1963; Cochrane, 1964; Job et al, 1964). As yet there is no satisfactory explanation of the mechanism of production of erythema nodosum leprosum. Among the many hypotheses postulated, the concept of an immunological reaction as the fundamental basis of this rather dramatic complication is generally accepted (Aguas, 1963; Skinsnes and Tsang, 1963; Cochrane, 1964; Job et al., 1964). There is some evidence to link up this phenomenon with autoimmunity, such as the presence of lupus erythematosus cell and rheumatoid factor in the sera of a proportion of these patients (Cathcart et al., 1961 ; Bonomo et al., 1965 ; Matthews and Trautman, 1965 ; Karat et al., 1966). Pain in the joints (arthralgia) is a common and well-documented feature of erythema nodosum leprosum (Cochrane, 1964; Job et al., 1964). Lele et al. (1965) described five cases of leprosy presenting as rheumatoid arthritis. Except for Case 4, none of their patients had erythema nodosum. The synovial biopsy was done in four out of the five cases, and the main histopathological finding was infiltration by round cells, epithelioid cells, and occasional giant cells. In the patient with erythema nodosurn synovial biopsy did not reveal any significant change. In the past two years at Schieffelin Leprosy Research Sanatorium we have seen 10 patients with lepromatous leprosy who developed acute painful exudative polyarthritis clinically similar to acute rheumatoid arthritis during the course of erythema nodosum leprosum. The polyarthritis cleared up completely when erythema nodosum subsided, leaving no residual signs of rheumatoid arthritis, clinical or radiological. We present the case reports of two of these patients who, during the course of erythema nodosum leprosum, developed acute exudative polyarthritis clinically simulating acute rheumatoid arthritis; in both of them synovial biopsies were carried out during the acute phase. The nearest to the description of this condition we can find is that of Davison (1961) and of Wheate (1962). Wheate gives the case report of one patient who had a unilateral small effusion into the knee joint and "ganglion-like swelling of the synovia of both wrists on the dorsal aspects."