Nerve involvement in Indian post kala-azar dermal leishmaniasis.

Abstract

Sir,Post kala-azar dermal leishmaniasis (PKDL) is a well-recognized sequel of kala-azar in India, developingin approximately 20% cases after a variable timeinterval of 1–5 years (1). The disease occurs chieflyin the eastern parts of India, an area that also hasa high prevalence of leprosy. PKDL manifests assymmetrically distributed hypopigmented macules,papules, infiltrated plaques and nodules, that bear aclose resemblance to leprosy, with which it is oftenconfused. Clinical and pathological features to differ-entiate the two diseases have been described (2).Nerve inflammation on skin biopsy is considered adiagnostic feature of leprosy. We describe a case ofIndian PKDL with lesional nerve infiltration, histolo-gically mimicking tuberculoid leprosy. The diagnosis ofPKDL was confirmed by serological and gene ampli-fication techniques. Nerve involvement has beenreported in the Sudanese variety of PKDL (3). As faras ascertained, this feature has not been previouslyreported in Indian PKDL.CASE REPORTA 25-year-old migrant labourer from Bihar presentedwith widespread, asymptomatic macular and papularlesions of 2 years duration. It was not associated withtingling, numbness or paraesthesia, fever or constitu-tional symptoms. He had kala-azar 10 years ago andwas treated with 24 intramuscular injections of sodiumantimony stibogluconate, with complete cure.Dermatological examination revealed multiple, dis-crete and coalescent, symmetrically distributed hypo-pigmented macules and papules, distributed on the faceincluding ear lobes, the trunk and extremities (Fig. 1).There was no lesional or glove and stocking anaesthesiaor peripheral nerve enlargement. Mucous membraneswere spared. Examination of the abdomen, cardio-vascular and central nervous systems revealed noabnormality.The haematological and biochemical investigationswere normal. Focal calcifications in the spleen wereobserved on ultrasonography of the abdomen, sugges-tive of previous kala-azar. Slit skin smears from thepapular lesions stained with Giemsa, acridine orangeand Ziehl Neelsen stains failed to demonstrateLeishman-Donovan (LD) bodies or acid-fast bacilli.A skin biopsy obtained from a papule, revealeda superficial and deep dermal, moderately dense,granulomatous infiltrate composed of epithelioid cellsand lymphocytes around the blood vessels, appendagesand nerve twigs. There were no plasma cells ormacrophages; LD bodies could not be demonstrated.On S-100 staining, fibrillar structures, suggestive ofnerve twigs, could be identified within the granulomas(Fig. 2). The histopathological features were suggestiveof tuberculoid leprosy. Enzyme-linked immunosorbentassay (ELISA) for PKDL and a strip test based onrecombinant K39 antigen (4) were positive. A 600-bpfragment of the Leishmania donovani-specific kineto-plast mini-circle DNA was amplified from the skinsample by polymerase chain reaction (PCR) (5).The diagnosis of PKDL was confirmed by serologicaland DNA amplification procedures. However, thepatient refused therapy, as he had to go back to hisvillage for financial reasons.DISCUSSIONThe remarkable clinical similarity between PKDL andleprosy is well known. The differentiating featuresinclude predilection of PKDL lesions for the centro-facial region, absence of neurological deficit bothclinically and histologically and demonstration of LDbodies in slit skin smears or histological sections.However, in various series on PKDL reported fromdifferent parts of the world, the parasite could bedemonstrated by slit smears in only 20–66.6% oflesions and on histopathology, the detection ratewas sometimes as low as 20% (6, 7). Under suchcircumstances, establishing the diagnosis of PKDL and