ENL or relapse in a BL/LL patient?

Leprosy Mailing List – May 3^rd, 2012

Ref.:   ENL or relapse in a BL/LL patient?
From: G Warren, Sydney, Australia

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Dear Salvatore,

I refer to the letter from Dr Kawuma in Uganda (LML May 3^rd, 2012).

Yes, definitely down grading reaction can occur and it frequently did in the “old days” when a patient was receiving one drug only, when the patient developed resistance to that drug.  In the 1960s it was usually dapsone but, also downgrading reaction occurred to some of the other drugs in which initial improvement had appeared to occur and then the patients would down grade till we changed the antileprosy drug therapy.  It usually required several years for such resistance to show up.

It also occurred in patients who had been given multidrug therapy because they were not responding to dapsone and so were considered dapsone resistant; though there was no ability to test for resistance to dapsone.  After a period often a year or two the disease seemed under control and the patient stopped drug therapy (often just by dropping out himself but sometimes by completing the 12 months recommended for MDT).  But after several years the patient would reappear with what was said to be ENL; but on careful testing one would find the bacteriological index (BI) was higher than it had been at the last test.

It is fascinating how one can separate between new lesions of downgrading BL/LL and the lesions of ENL that look similar.  Restarting adequate anti-leprosy medication especially including the use of clofazamine, seemed to rapidly deal with the problem that was apparently resistance to dapsone and the multidrug therapy had not been given long enough.

I hope that will help.  When a patient returns with what is queried to be ENL or relapse in a BL/LL patient who has completed the recommended 12 months MDT it is wise to check the lesions for infiltration, by pressing a glass slide onto the lesions.  The pressure of a slide will define the edge of the lesion.  If it is ENL there will be a well localised small patch of infiltration but, if it is a new lesion ie true relapse, it will not be so definite and not so erythematous.

We need to be on the watch for such relapses!

Grace Warren

Previously Superintendent Hong Kong Leprosarium 1960-1975.