Early LL might present as itching

Leprosy Mailing List,
May 22nd, 2009
Ref.: Early LL might present as itching
From: Bryceson A., London, UK

Dear Salvatore,

This is a very interesting discussion in response to Dr Pai's letter (LML April 25th, 2009), but is in danger of losing its focus.

The question is not whether patients with leprosy may itch; they may for the same reasons as patients without leprosy.

The question is whether itching may be a symptom of early lepromatous leprosy. This is the stage when the skin is becoming rapidly infiltrated with bacilli that are mulltiplying in dermal histiocytes and Schwann cells of peripheral nerve fibres. It was my first leprosy teacher Dr Richard Buker, who had great experience in Burma, Thailand and Laos, who told me that early LL might present as itching. I have seen this 3 or 4 times, and particularly recall an Ethiopian girl whose only symptom was that of itching; no skin lesions were visible; slit skin smears were full of AFB. It was because of these experiences that Roy Pfaltzgraff and I stated in our little text book "Leprosy" "Rarely, a short period of generalised itching may herald the onset of diffuse rapidly progressive lepromatous leprosy".

Stanley Browne, a stickler for accuracy and good English, very kindly sent me his review copy of the 1st edition. He had found about 10 errors on each page; but he allowed the sentence on itching.

So itching is a known symptom, and it has crept into a text book. But Dr Vijayakumaran and others are right; itching has many causes, and these need to be looked for, but not at the expense of missing leprosy.

Others have mentioned itching in association with reactions; itching is common after cutaneous inflammation from any cause. I have sometimes wondered why a hot wet climate may cause itching, with or without prickly heat; might the itching be due to stretching of dermal structures?

The argument has been raised that itching in leprosy is not genuine itching, but paresthesia. But then itching is a form of paresthesia. So we might not all interpret our symptoms in quite the same way. Ho do I know that what I see as yellow is the same as what you see yellow? So I don't think this argument is important. But I like Terence Ryan's comment (LML May 1st, 2009) that true itching leads to scratching and scratch marks. Perhaps we should look more closely at these patients in future. Fever plus nothing = typhoid until excluded.

Itching plus nothing might = lepromatous leprosy until excluded.

Anthony