Late lepromin reaction in untreated patients with indeterminate leprosy under 21 years old in Burma.

Studies on lepromin reactivity in indeterminate (I) leprosy have usually been carried out among patients in whom the disease appeared 1 or more years before testing. This may result in misleading findings because a high proportion of patients, probably those showing moderate or strong lepromin reactions, seem to progress to the tuberculoid pole of leprosy in a relatively short time (<1 year), and in many the lesions heal spontaneously. The object of the present study was to determine the frequency and intensity of late lepromin reactions (macroscopic readings) in untreated I patients aged under 21 years who had had the disease for less than 1 year. Of 209 patients tested with lepromin containing 160 x 10(6) bacilli/ml only a small proportion ( not equal 7%) showed a negative or doubtful lepromin reaction, while 61.5% were 2+ and 3+ reactors. These findings indicate that a favourable outcome may be expected in most I cases in the trial area.