Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Search in posts
Search in pages
Filter by Categories
15th National Conference of the IAOMFP, Chennai, 2006
Abstracts from current literature
Acne in India: Guidelines for management - IAA Consensus Document
Art & Psychiatry
Association Activities
Association Notes
Award Article
Book Review
Brief Report
Case Analysis
Case Letter
Case Letters
Case Notes
Case Report
Case Reports
Clinical and Laboratory Investigations
Clinical Article
Clinical Studies
Clinical Study
Conference Oration
Conference Summary
Continuing Medical Education
Cosmetic Dermatology
Current Best Evidence
Current Issue
Current View
Derma Quest
Dermato Surgery
Dermatosurgery Specials
Dispensing Pearl
Do you know?
Drug Dialogues
Editor Speaks
Editorial Remarks
Editorial Report
Editorial Report - 2007
Editorial report for 2004-2005
Fourth All India Conference Programme
From Our Book Shelf
From the Desk of Chief Editor
Get Set for Net
Get set for the net
Guest Article
Guest Editorial
How I Manage?
IADVL Announcement
IADVL Announcements
IJDVL Awards
IJDVL Awards 2018
IJDVL Awards 2019
IJDVL Awards 2020
IJDVL International Awards 2018
Images in Clinical Practice
In Memorium
Inaugural Address
Knowledge From World Contemporaries
Leprosy Section
Letter in Response to Previous Publication
Letter to Editor
Letter to the Editor
Letter to the Editor - Case Letter
Letter to the Editor - Letter in Response to Published Article
Letter to the Editor - Observation Letter
Letter to the Editor - Study Letter
Letter to the Editor - Therapy Letter
Letter to the Editor: Articles in Response to Previously Published Articles
Letters in Response to Previous Publication
Letters to the Editor
Letters to the Editor - Letter in Response to Previously Published Articles
Letters to the Editor: Case Letters
Letters to the Editor: Letters in Response to Previously Published Articles
Medicolegal Window
Miscellaneous Letter
Net Case
Net case report
Net Image
Net Letter
Net Quiz
Net Study
New Preparations
News & Views
Observation Letter
Observation Letters
Original Article
Original Contributions
Pattern of Skin Diseases
Pediatric Dermatology
Pediatric Rounds
Presedential Address
Presidential Address
Presidents Remarks
Report of chief editor
Report of Hon : Treasurer IADVL
Report of Hon. General Secretary IADVL
Research Methdology
Research Methodology
Resident page
Resident's Page
Resident’s Page
Residents' Corner
Residents' Corner
Residents' Page
Review Article
Review Articles
Reviewers 2022
Revision Corner
Self Assessment Programme
Seminar: Chronic Arsenicosis in India
Seminar: HIV Infection
Short Communication
Short Communications
Short Report
Special Article
Specialty Interface
Study Letter
Study Letters
Symposium - Contact Dermatitis
Symposium - Lasers
Symposium - Pediatric Dermatoses
Symposium - Psoriasis
Symposium - Vesicobullous Disorders
Symposium Aesthetic Surgery
Symposium Dermatopathology
Symposium-Hair Disorders
Symposium-Nails Part I
Symposium-Nails-Part II
Systematic Review and Meta-Analysis
Systematic Reviews and Meta-analyses
Systematic Reviews and Meta-analysis
Therapeutic Guideline-IADVL
Therapeutic Guidelines
Therapeutic Guidelines - IADVL
Therapy Letter
Therapy Letters
View Point
What’s new in Dermatology
View/Download PDF

Translate this page into:

Observation Letter
89 (
); 298-300

Role of molecular approaches to distinguish post kala-azar dermal leishmaniasis from leprosy: A case study

Department of Pharmacology, Institute of Postgraduate Medical Education and Research, Kolkata, Kolkata, West Bengal, India
Department of Biotechnology, National Institute of Biomedical Genomics, Kalyani, Kolkata, West Bengal, India
Department of Microbiology, Sarat Chandra Chattopadhyay Government Medical College and Hospital, Uluberia, Howrah, Kolkata, West Bengal, India
Department of Tropical Medicine, School of Tropical Medicine, Kolkata, West Bengal, India
Corresponding author: Prof. Mitali Chatterjee, Department of Pharmacology, Institute of Postgraduate Medical Education and Research, 244 B, AJC Bose Road, Kolkata 700 020, West Bengal, India.
This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

How to cite this article: Roy S, Roy M, Nath S, Chaudhuri SJ, Ghosh MK, Mukherjee S, et al. Role of molecular approaches to distinguish post kala-azar dermal leishmaniasis from leprosy: A case study. Indian J Dermatol Venereol Leprol 2023;89:298-300.


Visceral leishmaniasis, or kala-azar, is caused by the kinetoplastid parasite Leishmania donovani and its dermal sequel, post kala-azar dermal leishmaniasis appears after apparent cure from visceral leishmaniasis. Post kala-azar dermal leishmaniasis (PKDL) in South Asia occurs in approximately 10% of cases with a lag period following visceral leishmaniasis that ranges from 2 to 10 years.1 PKDL presents with either macular lesions or a combination of papules, nodules and macules, termed polymorphic. In visceral leishmaniasis endemic areas, cases of leprosy or Hansen’s disease caused by Mycobacterium leprae can present with similar macular or nodular lesions, along with nerve thickening and hypoesthesia, thus posing a diagnostic dilemma.2 As per the World Health Organization algorithm for diagnosis of post kala-azar dermal leishmaniasis, the criteria include a history of visceral leishmaniasis, rK39 immunochromatographic strip test positivity, presence of amastigotes in slit skin smears, direct agglutination test and/or ELISA positivity ( In view of the clinical dilemma, molecular approaches like quantitative real-time polymerase chain reaction and Sanger sequencing are employed to reach a conclusive diagnosis.

During an active field survey and medical camp conducted in Harirampur block, South Dinajpur district, West Bengal, a 36-year-old male presented with a macular hypoesthetic patch on the lower right side of back. The lesion was present for eight years along with ulnar nerve thickening [Figures 1a and b]. At presentation, the patient had no fever, hepatosplenomegaly or lymphadenopathy, but gave a history of visceral leishmaniasis 32 years ago for which he received sodium antimony gluconate.

Figure 1a:: A 36-year old male with an isolated macular hypoesthetic patch on lower right back
Figure 1b:: Magnified view of the macular lesion on lower right back

The rK39 dipstick was positive and DNA was isolated from a 4 mm skin biopsy. Primers for Leishmania specific Internal Transcribed Spacer-1 gene (LITSR 5’-CTGGATCATTTTCCGATG-3’, L5.8S 5’-TGATACCACTTATCGCACTT-3’)3 and kinetoplastid minicircle gene (kDNA F: 5’-CTTTTCTggTCCTCCgggTAgg-3’; kDNA R: 5’-CCACCCggCCCTATTTTACACCAA-3’) along with a 5’FAM tagged probe (5’-6FAMTTTTCgCAgAACgCCCCTACCCgC-BBQ were used to perform polymerase chain reaction and quantitative real-time polymerase chain reaction, respectively.4 The Internal Transcribed Spacer-1 polymerase chain reaction 320 base pair (bp) product was visualised by 2% agarose gel electrophoresis, while the cycle threshold for the suspected case was 17.42. The Leishmania donovani WHO reference strain MHOM/IN/80/DD8 was a positive control and was positive by Internal Transcribed Spacer-1 polymerase chain reaction and quantitative polymerase chain reaction, cycle threshold being 20.19. The non-template control was undetermined. For quantification of parasite load, a standard curve was generated by serially diluting DNA isolated from 1 × 107 Leishmania donovani parasites and a quantitative polymerase chain reaction was performed.3

A Mycobacterium leprae-specific repetitive element (RLEP) based Taqman quantitative polymerase chain reaction was similarly undertaken using Mycobacterium leprae specific primers (RLEP-F: 5’-gCAgTATCgTgTTAgTgAA-3’; RLEP-R: 5’-CgCTAgAAggTTgCCgTATg-3’) and 5’FAM tagged probe (5’-6FAM-CgCCgACggCCggATCATCgABBQ) with a Mycobacterium leprae TN strain being the positive control.5 Cycle threshold value of the positive control was 27.99 and for the case, it was undetermined, confirming the patient was negative for leprosy [Figure 2].

Figure 2:: A proposed algorithm to distinguish post kala-azar dermal leishmaniasis from leprosy. BLAST, Basic local alignment search tool; ITS-1, Internal transcribed spacer-1; kDNA, Kinetoplast DNA; MEGA, Molecular evolutionary genetics analysis software; NCBI, National Center for Biotechnology Information; PCR, Polymerase chain reaction; RLEP, M. leprae-specific repetitive element

To confirm the Leishmania species, cycle sequencing and capillary electrophoresis was undertaken. Briefly, the chromatogram obtained was converted into a fast alignment file and analysed using Molecular evolutionary genetics analysis. Reference sequences of Internal Transcribed Spacer-1 of different species of Leishmania were retrieved from GenBank ( and aligned with the patient sequence via ClustalW and Molecular evolutionary genetics analysis software version 11.0 (Accession numbers KJ465104.1, KJ465105.1, MN244152.1 for Leishmania donovani, MH347947.1 for Leishmania tropica and KJ002553.1 for Leishmania. major). The patient’s sequence aligned with Leishmania donovani sequences. Furthermore, a BLAST search showed a 99.9% match with Leishmania donovani (Accession number KJ465105.1). (, Figure 3). The patient’s sequence was submitted to GenBank (Accession number ON817264).

Figure 3:: BLAST alignment of sequence sourced from the patient (Accession number ON817264) and Leishmania donovani sequence having accession number KJ465105.1 (98.9% match). BLAST, Basic local alignment search tool

Post kala-azar dermal leishmaniasis cases form a relatively neglected component of the ongoing visceral leishmaniasis elimination programme, but being potent reservoirs for disease transmission, need urgent attention. The identification of macular post kala-azar dermal leishmaniasis is challenging as their hypopigmented lesions mimic leprosy.6 As this patient presented with a single hypopigmented hypoesthetic patch and ulnar thickening, strongly suggestive of leprosy along with a prior history of visceral leishmaniasis, quantitative polymerase chain reaction for post kala-azar dermal leishmaniasis and leprosy was necessary. The positivity of rK39, Internal Transcribed Spacer-1 polymerase chain reaction and quantitative polymerase chain reactionR confirmed Leishmania infection. Additionally, as the quantitative polymerase chain reaction of Mycobacterium leprae specific repetitive element was negative, it corroborated this was a case of post kala-azar dermal leishmaniasis, masquerading as leprosy. As it was a single lesion, the causative species could have been Leishmania donovani, Leishmania major or Leishmania tropica. Therefore, it was necessary to define the causative species which was facilitated by Sanger sequencing, and confirmed the causative organism was Leishmania donovani.7

Due to the considerable overlap between macular post kala-azar dermal leishmaniasis and leprosy, and the prolonged period of therapy necessary, multiple molecular approaches were applied for confirming the causative organism. Nerve inflammation and peripheral nerve involvement are symptoms suggestive of leprosy, but neural involvement has been reported in Sudanese post kala-azar dermal leishmaniasis8 as also in a case from Bihar.9 Additionally, symptoms of leprosy can also overlap with psoriasis, pityriasis versicolor, granuloma annulare, syphilis, vitiligo and sarcoidosis.10 Taken together, suspected leprosy or post kala-azar dermal leishmaniasis cases should ideally be tested for other diseases to ensure effective case management.


We are thankful to the Department of Health and Family Welfare, West Bengal, for providing technical and personal support during the field surveys.

Ethical approval

The study was approved by the Institutional Ethics Committee.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms.

Conflict of interest

There are no conflicts of interest.

Financial support and sponsorship

This work was supported by the Indian Council of Medical Research, Govt. of India (Grant number: 6/9–7 [151] 2017– ECD II and 6/9–7(263)KA/2021/ECD–II);); Fund for Improvement of S&T infrastructure in Universities and Higher Educational Institutions (FIST) Program, Dept. of Science and Technology, Govt. of India (DST–FIST) (Grant number: SR/FST/LS1–663/2016); Dept. of Science and Technology, Govt. of West Bengal (Grant number: 969[Sanc.]ST/P/ S&T/9G–22/2016); Dept. of Science and Technology, Govt. of India and German Academic Exchange Service (DST–DAAD). MC is a recipient of a JC Bose Fellowship (JCB/2019/000043), Science Engineering & Research Board, DST, Govt. of India.


  1. , , , . Post-kala-azar dermal leishmaniasis--an overview. Int J Dermatol. 2010;49:921-31.
    [CrossRef] [PubMed] [Google Scholar]
  2. , . The clinical and immunological features of leprosy. Br Med Bull 200677-78, 103-21
    [CrossRef] [PubMed] [Google Scholar]
  3. , , , , , et al. Monitoring of parasite kinetics in Indian post-Kala-azar dermal leishmaniasis. Clin Infect Dis. 2018;66:404-10.
    [CrossRef] [PubMed] [Google Scholar]
  4. , , , , , , et al. Serological and molecular tools to diagnose visceral leishmaniasis: 2-years' experience of a single center in Northern Italy. PLoS One. 2017;12:e0183699.
    [CrossRef] [PubMed] [Google Scholar]
  5. , , , , , . Enumeration of Mycobacterium leprae using real-time PCR. PLoS Negl Trop Dis. 2008;2:e328.
    [CrossRef] [PubMed] [Google Scholar]
  6. , , , et al. In-situ immune profile of polymorphic vs. macular Indian post kala-azar dermal leishmaniasis. Int J Parasitol Drugs Drug Resist. 2019;11:166-76.
    [CrossRef] [PubMed] [Google Scholar]
  7. , , . Cutaneous manifestations of human and murine leishmaniasis. Int J Mol Sci. 2017;18:1296.
    [CrossRef] [PubMed] [Google Scholar]
  8. , , , , , . Post-kala-azar dermal leishmaniasis in the Sudan: Peripheral neural involvement. Int J Dermatol. 1992;31:400-3.
    [CrossRef] [PubMed] [Google Scholar]
  9. , , , , , . Nerve involvement in Indian post kala-azar dermal leishmaniasis. Acta Derm Venereol. 2004;84:245-6.
    [CrossRef] [PubMed] [Google Scholar]
  10. , , . Leprosy masquerading as tinea faciale. Ann Natl Acad Med Sci (India). 2022;58:50-1.
    [CrossRef] [Google Scholar]

Fulltext Views

PDF downloads
View/Download PDF
Download Citations
Show Sections