Drs. Kumarasinghe reply: should large lesions of leprosy be considered as "Multibacillary" for treatment purposes even if the total number of lesions is less than five?
To the Editor:
We thank Souza Santos, et al. for their interest in our article (5). While agreeing with some points made by them, it seems that they have misunderstood some of the points we made.
First, our recommendation of "considering large lesions of leprosy as multibacillary" was not aimed for teaching hospital settings where microbiological and histopathological facilities and good clinical expertise are available, but for field settings, in areas where treatment is initiated without any investigations, purely based on the number of hypopigmented lesions. At the teaching hospitals and tertiary care centers we also treat patients after considering the smear results and skin biopsy results, in addition to the clinical picture.
It is well known that even a single lesion can be multibacillary (3, 4, 6). The rationale of total number of lesions as the only criterion for deciding on the treatment type, as well as for scientific analyses has been questioned (8). However, in a retrospective study carried out in India, Gift, et al. have found that World Health Organization (W.H.O.) operational classification is a satisfactory method for deciding on the form of treatment (2). In this analysis, they have taken the smear examination as the gold standard for evaluating the sensitivity and specificity of the W.H.O. operational classification. However, where the larger lesions (>10 cm) were present they have found that the specificity was 91.2% although the sensitivity was low. As only 4.9% of smear positive cases have had records of the size of the lesion, that study appears to be inadequate to evaluate the validity of the size of lesions as an additional parameter.
Our recommendation for treatment of large plaque leprosy with three drugs for one year ("multibacillary treatment") is based on the observation of more relaspses in this group of patients who have been treated with two drugs for six months. In another study conducted in Sri Lanka it was shown that several patients with large lesions (>10cm) of leprosy were smear positive although the total number of the patches was less than five (1).
We do not dispute that many cases of paucibacillary leprosy have less than 5 patches. Although the authors agree on the W.H.O. operational classification based on the number of patches, the case described by the authors, with a large plaque of leprosy plus 5 other lesions on the face, would have been classified as "multibacillary", if the microbiological investigations were not done, going by the visual classification recommended by the W.H.O. It is known that some cases of leprosy may improve even with dapsone monotherapy (as was the practice before the advent of multi-drug therapy, M.D.T.), or single dose multidrug therapy. It would be interesting to see the long term outcome of the case presented by the authors. Even though a smear was negative, in the case presented by the authors, we would have not have been comfortable in administering paucibacillary treatment only for 6 months, in a patient with such extensive lesions. Cell mediated immunity is of paramount importance in the pathogenesis of leprosy (7). It is clear that patients progress in the leprosy spectrum towards the lepromatous pole when the immunity of the host is unable to overcome the infection by lepra bacilli. In cases of subpolar lepromatous leprosy some areas with typical hypopigmented semianaesthetic lesions can often be seen while other smear positive lesions coexist in the same patient. Clearly not all cases of multibacillary leprosy start as polar lepromatous leprosy. In our statement in the article we did not imply that "polar tuberculoid leprosy" would downgrade to "polar lepromatous leprosy" which are generally immunologically stable.
We agree with the authors that a larger scale study would be helpful to resolve the issue whether larger lesions due to leprosy should be treated with the "multibacillary drug regime" at least for one year.
A representative lesion should be micro-biologically and histopathologically evaluated whenever possible, and the findings should be evaluated in conjunction with the clinical features before commencing on treatment. The current W.H.O. operational classification; while being useful in the community perspective, appears to be an over-simplification in some situations. The search for any additional features to fine tune the parameters should be continued.
—S. Prasad W. Kumarasinghe
Senior Consultant Dermatologist,
National Skin Centre, Singapore
—M. P. Kumarasinghe
Senior Consultant Pathologist,
Singapore General Hospital, Singapore
REFERENCES
1. ARIYAWANSA, D., SATGURUNATHAN, K., and WASALAARACHCHI, K. Should the size of the lesion be considered as an additional factor in the clinical diagnosis of leprosy? 3rd South Asian Regional Association of Dermatology Conference, Colombo, Sri Lanka, 2003.
2. GIFT, N., JOSEPH, G., and RICHARD, J. Validity of the W.H.O. operational classification and value of other clinical signs in the classification of leprosy. Int. J. Lepr. Other Mycobact. Dis. 72 (2004) 278283.
3. JOB, C. K., KAHKOHEN, M. E., JACOBSON, R. R., and HASTINGS, R. C. Single lesion subpolar lepromatous leprosy and its possible mode of origin. Int J Lepr. Other Mycobact. Dis. 57 (1989) 1219.
4. KAR, B. K., BELIAPPA, P. R., EBENIZER, G., and JOB, C. K. Single lesion borderline lepromatous leprosy. Int. J. Lepr. Other Mycobact. Dis. 72 (2004) 4547.
5. KUMARASINGHE, S. P..W., and KUMARASINGHE, M. P. Should large lesions of leprosy be considered as multibacillary for treatment of treatment purposes even if the total number of lesions is less than five? Int. J. Lepr. Other Mycobact. Dis. 72 (2004) 173174.
6. MISRA, R. S., RAVIS, S., IYERHGAR, B., and NASH, I. A histopathological and immunological profile of a single lesion lepromatous leprosy. Int J Lepr. Other Mycobact. Dis. 59 (1991) 645648.
7. RIDLEY, D. S. Pathogenesis of leprosy and related diseases. London: Wright, 1988. p. 5558.
8. SCOLLARD, D. M. Classification of leprosy: a full color spectrum, or black and white? Int. J. Lepr. Other Mycobact. Dis. 72 (2004) 166168.
Reprint requests to
S. Prasad W. Kumarasinghe, MBBS, MD, FCCP, FAMS, Senior consultant Dermatologist
1 Mandalay Road
National Skin Centre, Singapore
E-mail: prasadkumarasinghe@yahoo.com