Decreased cutaneous resonance running time in cured leprosy subjects.

BACKGROUND/OBJECTIVES Leprosy prominently involves both the skin and peripheral neural tissues and some symptoms persist after microbial cure. Because alterations in the dermis also occur in leprosy, we assessed here whether there were changes in cutaneous resonance running time (CRRT), a parameter that is influenced by collagen properties, in cured leprosy subjects. METHODS A reviscometer was used to measure the CRRT at various directions on the dorsal hand and the flexural forearms of 76 cured leprosy subjects aged 50-85 years and 68 age-matched normal subjects. RESULTS In comparison to normal subjects, CRRTs on the hands and the forearms were significantly reduced in all directions in cured leprosy, except at the 1-7, 2-8 and 3-9 o'clock directions on the forearms. CRRTs were reduced significantly at both the 4-10 and 5-11 o'clock directions on the forearm in lepromatous (73.33 +/- 4.19 at 4-10 o'clock and 67.44 +/- 2.71 at 5-11 o'clock direction) and borderline lepromatous types (77.58 +/- 5.84 at 4-10 o'clock and 79.85 +/- 6.81 at 5-11 o'clock direction) as compared with normal (143.10 +/- 7.75 at 4-10 o'clock and 125.18 +/- 8.14 at 5-11 o'clock direction). On the hand, CRRTs at all directions, except that at 4-10 o'clock direction, were also significantly reduced in lepromatous and borderline lepromatous types in comparison with normal. Significant differences in CRRT at some directions were found among the various subtypes of leprosy. CONCLUSION CRRTs were abnormal in the cured leprosy subjects as a whole, but varied with leprosy subtypes, which suggested that the extent of reduction of CRRTs correlates with the severity of immune alteration. These results suggest that CRRT measurements could be a useful approach to quantify the extent of some residual abnormalities in cured leprosy and perhaps could also be used to evaluate the efficacy of treatment.