Itching in leprosy ?

Leprosy Mailing List,
May 30th, 2009
Ref.: Itching in leprosy ?
From: Vijayakumaran P., Chennai, India

Dear Dr. Noto,

This is really an interesting discussion. "Fever plus nothing = typhoid until excluded. Itching plus nothing might = lepromatous leprosy until excluded." (Bryceson A. LML May 22nd , 2009).

This seems to be a nice argument.

Many of us must have seen persons with extensive scabies infestation or fungal dermatosis without scratch marks. Tolerance level varies widely among people. Some cannot tolerate mild itching. Others are comfortable even with severe itchy conditions. There was a study undertaken in south India several years ago (not published) when the prevalence of leprosy was high. It intended to correlate clinical suspicion of infiltration for early diagnosis of early lepromatous leprosy. The study was conducted in an area served by a Non-Governmental-Organisation implementing the National Leprosy Eradication Programme with 20 leprosy field workers, four supervisors and a Medical Officer.

Majority of the staff were engaged in leprosy work for more than 10 years. They did a survey in few selected villages looking for infiltration in the face. Several persons were listed as having suspected infiltration by these experienced workers. Slit-skin smear examination revealed that none of them was positive for AFB and hence not leprosy. What the "experienced" eyes see can also be deceiving. Manifestation of leprosy is a slow process more so in lepromatous leprosy.

General teaching is that multiplication of leprosy bacilli is very slow. I understand that rapid infiltration is a sign of lepra reaction. If itching were a sign of infiltration then it should have been a presenting symptom for all types of leprosy skin lesions. 1. Presenting complaint from the affected person is joint pain in many instances where it is actually neuritis. 2. Bleeding from nose may be a presenting symptom of lepromatous leprosy 3. Tingling sensation is interpreted as pain by many which can happen in neuritis. It does not mean that one should suspect leprosy in a person when presenting symptom is joint pain etc.

A common observation is that eyes do not see what the mind does not know. Even if mind does know, the presentation can be masked by many other skin conditions. Several such instances have been reported in previous communications. I like to sound caution that this concept of itching may mislead health workers or medical personnel in his/her diagnostic capabilities.

The equation formulated by Dr. Anthony Bryceson can be a good research question.

Vijayakumaran P