The diagnosis of leprosy is not always easy

Ref.:   The diagnosis of leprosy is not always easy

From: B Naafs, Munnekeburen, The Netherlands

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Dear Salvatore,

I refer to last week messages about early diagnosis of lepromatous leprosy.  Kindly, find in attachment the paper of J A da Costa Nery et al. “Hansen’s disease in a general hospital: uncommon presentations and delay in diagnosis” J Eur Acad Dermatol Venereol 2009 Feb;23 (2):150-6. Epub 2008 Sep 10.  I would be very grateful if you forward it to the leprosy mailing list.

The diagnosis of leprosy is not always easy, as it is generally stated and thought. To be aware that a condition or complaint could be leprosy is a start.  As leprosy is suspected it has to be proven.  The cardinal signs of leprosy have to be investigated.  They are loss of sensation in a skin lesion, enlarged peripheral nerves and positive slit-skin smear examination (*).  When two of these three signs are positive, leprosy is diagnosed. 

Ninety nine per cent of all leprosy patients can be diagnosed in the above mentioned way.  Herewith I will say a few words about one exception (indeterminate leprosy) and, two particular conditions namely: early lepromatous leprosy and diffuse lepromatous leprosy (also called Lapati’s leprosy or “Lepra bonita”).

Indeterminate leprosy

The diagnosis of indeterminate leprosy depends on awareness. Loss of sensation is often hardly present or is absent, nerves are not enlarged and skin smear is negative.  Even biopsy may be hardly helpful.  It is “the time that makes the diagnosis” and thus careful follow-up of the patient is needed for a few months.

Early lepromatous (LL) leprosy

In an early state LL leprosy is often not diagnosed, though these patients can be extremely infective.  Awareness and skin smear may be of help.  When people do not think of leprosy it can be easily missed. 

Diffuse lepromatous leprosy (Lapati’s leprosy)

In early and late diffuse lepromatous leprosy mostly nothing is to be seen or found, only the patient may complain of some aches and pain or having the feeling of dropping things or of sleeping skin.  In late diffuse leprosy the patient looks younger and has a smooth skin due to infiltration [lepra bonita].  Skin smears in both groups of patients are positive.

Nery’s  paper addresses these problems.  Herewith I report part of the conclusions:-

<< Multibacillary (MB) leprosy, especially close to the lepromatous end of the spectrum, may mimic other diseases, and the patient cannot be diagnosed without a biopsy or a slit skin smear examination.  Leprosy should be considered in all patients with skin lesions not responding to treatment, especially when they have neurological deficits, and live or have lived in a leprosy endemic area. >>

Ben Naafs

(*)

The Diagnosis of Leprosy

S Noto, P A M Schreuder and B Naafs

Leprosy mailing list - October 2011