Indeterminate leprosy

Leprosy Mailing List – September 17^th, 2010

Ref.:   Indeterminate leprosy

From: Shumin Chen, Jinan, Shandong, China  

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Dear Dr Noto,

  

Indeterminate leprosy is difficult in diagnosis both clinically and pathologically (G. Warren LML Mar. 28th, 2010).  When a case is suspected and pathological examination shows negative AFB, series slices should be made and careful looking for destroyed neurofibres; an evidence for nerve damage, which may be helpful in the diagnosis of indeterminate leprosy.  When necessary, S-100 protein staining should be made in confirmation of nerve damage.

About the usefulness of dermal nerve damage and S-100 protein in the early diagnosis of leprosy, some papers on this topic in Medline can be found.  Here are two examples related to the diagnosis of indeterminate leprosy: 1. Weng XY, et al. Immuo-histopatholgy in the diagnosis of early leprosy. Int J Lepr, 1999; 68(4):426-433. 2. Gupta SK, et al. S-100 protein as a useful auxiliary diagnostic aid in tuberculoid leprosy. J Cutan Pathol, 2006; 33(7):482-486.

In the textbook of "Leprosy" edited by Hastings, we can find following description regarding the diagnosis of indeterminate leprosy: Histologically there is a scattered infiltration of lymphocytes and histocytes around skin appendages, peripheral nerves and vessels which is diagnosable as leprosy in cases exhibiting a cellular reaction within a dermal nerve, .......(p 91).

In Shandong, when a suspected indeterminate leprosy, difficult case, is found, we usually take one out two strategies in dealing with the patient. One is to treat, the case with MDT and follow up to see the change of the skin lesion, but not label him or her, (as also suggested by Dr Warren).  Another strategy is just to closely follow up (no treatment) to see the change, and then, action will be taken accordingly.

Sincerely yours,

Dr. Shumin Chen 

Shandong provincial Institute of Dermatology

Jinan, Shandong, China