Dermatologic Manifestations of Leprosy
- Author: Felisa S Lewis, MD; Chief Editor: Dirk M Elston, MD more...
Background
Leprosy is a chronic granulomatous disease principally affecting the skin and peripheral nervous system. Leprosy is caused by infection with Mycobacterium leprae. Although much improved in the last 25 years, knowledge of the pathogenesis, course, treatment, and prevention of leprosy continues to evolve. The skin lesions and deformities were historically responsible for the stigma attached to leprosy. However, even with proper multidrug therapy (MDT), the consequent sensory and motor damage results in the deformities and disabilities associated with leprosy.
The earliest description of leprosy comes from India around 600 BCE. Leprosy was then described in the Far East around 400 BCE. In the fourth century, leprosy was imported into Europe, where its incidence peaked in the 13th century. Leprosy has now nearly disappeared from Europe. Affected immigrants spread leprosy to North America.
Armauer Hansen discovered M leprae in Norway in 1873. M leprae was the first bacillus to be associated with human disease. Despite this discovery, leprosy was not initially thought to be an infectious disease.
In 2009, the discovery of a new cause of leprosy, Mycobacterium lepromatosis, was announced. Genetically, M leprae and M lepromatosis are very similar, but M lepromatosis causes the diffuse form lepromatous leprosy found in Mexico and the Caribbean.[1]
Humans are the primary reservoir of M leprae. Animal reservoirs of leprosy have been found in 3 species: 9-banded armadillos, chimpanzees, and mangabey monkeys.
Other articles on leprosy include Leprosy (neurology focus), Neuropathy of Leprosy, and Leprosy (infectious diseases focus).
Pathophysiology
Leprosy is not a highly infectious disease. The principal means of transmission is by aerosol spread from infected nasal secretions to exposed nasal and oral mucosa. Leprosy is not generally spread by means of direct contact through intact skin, although close contacts are most vulnerable.
However, in 2011, a unique strain of M leprae was genotyped in both humans and wild armadillos infected in the southern United States, suggesting a direct means of transmission. Several people had distinct contact with armadillos, including hunting, cooking, or eating armadillos.[2]
The incubation period for leprosy is 6 months to 40 years or longer. The mean incubation period is 4 years for tuberculoid leprosy and is 10 years for lepromatous leprosy.
The areas most commonly affected by leprosy are the superficial peripheral nerves, skin, mucous membranes of the upper respiratory tract, anterior chamber of the eyes, and the testes. These areas tend to be cool parts of the body. Tissue damage depends on the degree to which cell-mediated immunity is expressed, the type and extent of bacillary spread and multiplication, the appearance of tissue-damaging immunologic complications (ie, lepra reactions), and the development of nerve damage and its sequelae.
M leprae is an obligate intracellular, acid-fast, gram-positive bacillus with an affinity for macrophages and Schwann cells. For Schwann cells in particular, the mycobacteria bind to the G domain of the alpha-chain of laminin 2 (found only in peripheral nerves) in the basal lamina. Their slow replication within the Schwann cells eventually stimulates a cell-mediated immune response, which creates a chronic inflammatory reaction. As a result, swelling occurs in the perineurium, leading to ischemia, fibrosis, and axonal death.
The genomic sequence of M leprae was only completed within the last few years. One important discovery is that although it depends on its host for metabolism, the microorganism retains genes for the formation of a mycobacterial cell wall. Components of the cell wall stimulate a host immunoglobulin M antibody and cell-mediated immune response, while also moderating the bactericidal abilities of macrophages.
The strength of the host's immune system influences the clinical form of the disease. Strong cell-mediated immunity (interferon-gamma, interleukin [IL]–2) and a weak humoral response results in mild forms of disease, with a few well-defined nerves involved and lower bacterial loads. A strong humoral response (IL-4, IL-10) but relatively absent cell-mediated immunity results in lepromatous leprosy, with widespread lesions, extensive skin and nerve involvement, and high bacterial loads. Therefore, a spectrum of disease exists such that cell-mediated immunity dominates in mild forms of leprosy and decreases with increasing clinical severity. Meanwhile, humoral immunity is relatively absent in mild disease and increases with the severity of disease.
Toll-like receptors (TLRs) may also play a role in the pathogenesis of leprosy.[3]M leprae activates TLR2 and TLR1, which are found on the surface of Schwann cells, especially with tuberculoid leprosy. Although this cell-mediated immune defense is most active in mild forms of leprosy, it is also likely responsible for the activation of apoptosis genes and, consequently, the hastened onset of nerve damage found in persons with mild disease. Alpha-2 laminin receptors found in the basal lamina of Schwann cells are also a target of entry for M leprae into these cells, while activation of the ErbB2 receptor tyrosine kinase signaling pathway has been identified as a mediator of demyelination in leprosy.[4]
The activation of macrophages and dendritic cells, both antigen-presenting cells, is involved in the host immune response to M leprae. IL-1beta produced by antigen-presenting cells infected by mycobacteria has been shown to impair the maturation and function of dendritic cells.[5] Because bacilli have been found in the endothelium of skin, nervous tissue, and nasal mucosa, endothelial cells are also thought to contribute to the pathogenesis of leprosy. Another pathway exploited by M leprae is the ubiquitin-proteasome pathway, by causing immune cell apoptosis and tumor necrosis factor (TNF)–alpha/IL-10 secretion.[6]
Other pathways that may be involved are the vitamin D receptor (VDR), transforming growth factor (TGF)–beta, and NOD2-mediated signaling pathways.[7, 8]
A sudden increase in T-cell immunity is responsible for type I reversal reactions. Type II reactions result from activation of TNF-alpha and the deposition of immune complexes in tissues with neutrophilic infiltration and from complement activation in organs. One study found that cyclooxygenase 2 was expressed in microvessels, nerve bundles, and isolated nerve fibers in the dermis and subcutis during reversal reactions.[9]
Epidemiology
Frequency
United States
Approximately 6000 patients with leprosy live in the United States. Approximately 95% of these patients acquired their disease in developing countries. In the United States, 200-300 cases of leprosy are reported each year. States with large immigrant populations (eg, California, New York, Florida) have the largest number of new cases of leprosy. Small endemic foci of leprosy exist in Texas, Louisiana, and Hawaii.
International
The worldwide prevalence of leprosy is reported to be just less than 1 case per 10,000 population. Most affected persons live in the tropics and subtropics. Six major countries in Asia, Africa, and South America have not achieved the goal of elimination (< 1 case per 10,000 population). Approximately 86% of reported cases are found in 11 countries: Bangladesh, Brazil, China, Democratic Republic of the Congo, Ethiopia, India, Indonesia, Nepal, Nigeria, Philippines, and the United Republic of Tanzania. Overall, the prevalence of leprosy has decreased since the introduction of short-course MDT in 1982. The global annual detection rate for leprosy has also been declining since 2001.
Mortality/Morbidity
If severe and left untreated, leprosy can cause clinically significant and debilitating deformity. Since 1943, when sulfone was introduced as the first effective treatment for leprosy, antibiotic treatment has dramatically improved patients' outcomes. Early diagnosis and effective antimicrobial treatment can arrest and even cure leprosy.
Race
Leprosy occurs in persons of all races. African blacks have a high incidence of the tuberculoid form of leprosy. People with light skin and Chinese individuals tend to contract the lepromatous type of leprosy. Leprosy is endemic in Asia, Africa, the Pacific basin, and Latin America (excluding Chile). Leprosy is more a rural than urban disease.
Sex
In adults, the lepromatous type of leprosy is more common in men than in women after puberty, with a male-to-female ratio of 2:1. In children, the tuberculoid form of leprosy predominates and no sex preference is reported. Women tend to have a delayed presentation, which increases rates of deformity.
Age
Leprosy has a bimodal age distribution, with peaks at ages 10-14 years and 35-44 years. Leprosy is rare in infants. Children appear to be most susceptible to leprosy and tend to have the tuberculoid form.
Han XY, Sizer KC, Thompson EJ, Kabanja J, Li J, Hu P, et al. Comparative sequence analysis of Mycobacterium leprae and the new leprosy-causing Mycobacterium lepromatosis. J Bacteriol. Oct 2009;191(19):6067-74. [Medline]. [Full Text].
Truman RW, Singh P, Sharma R, et al. Probable zoonotic leprosy in the southern United States. N Engl J Med. Apr 28 2011;364(17):1626-33. [Medline].
McInturff JE, Modlin RL, Kim J. The role of toll-like receptors in the pathogenesis and treatment of dermatological disease. J Invest Dermatol. Jul 2005;125(1):1-8. [Medline].
Tapinos N, Ohnishi M, Rambukkana A. ErbB2 receptor tyrosine kinase signaling mediates early demyelination induced by leprosy bacilli. Nat Med. Aug 2006;12(8):961-6. [Medline].
Makino M, Maeda Y, Mukai T, Kaufmann SH. Impaired maturation and function of dendritic cells by mycobacteria through IL-1beta. Eur J Immunol. Jun 2006;36(6):1443-52. [Medline].
Fulco TO, Lopes UG, Sarno EN, Sampaio EP, Saliba AM. The proteasome function is required for Mycobacterium leprae-induced apoptosis and cytokine secretion. Immunol Lett. May 15 2007;110(1):82-5. [Medline].
Goulart LR, Goulart IM. Leprosy pathogenetic background: a review and lessons from other mycobacterial diseases. Arch Dermatol Res. Feb 2009;301(2):123-37. [Medline].
Zhang FR, Huang W, Chen SM, et al. Genomewide association study of leprosy. N Engl J Med. Dec 31 2009;361(27):2609-18. [Medline].
Pesce C, Grattarola M, Menini S, Fiallo P. Cyclooxygenase 2 expression in vessels and nerves in reversal reaction leprosy. Am J Trop Med Hyg. Jun 2006;74(6):1076-7. [Medline].
Khambati FA, Shetty VP, Ghate SD, Capadia GD. Sensitivity and specificity of nerve palpation, monofilament testing and voluntary muscle testing in detecting peripheral nerve abnormality, using nerve conduction studies as gold standard; a study in 357 patients. Lepr Rev. Mar 2009;80(1):34-50. [Medline].
Britton WJ, Lockwood DN. Leprosy. Lancet. Apr 10 2004;363(9416):1209-19. [Medline].
Ishii N. Recent advances in the treatment of leprosy. Dermatol Online J. Mar 2003;9(2):5. [Medline]. [Full Text].
Haroon N, Agarwal V, Aggarwal A, Kumari N, Krishnani N, Misra R. Arthritis as presenting manifestation of pure neuritic leprosy--a rheumatologist's dilemma. Rheumatology (Oxford). Apr 2007;46(4):653-6. [Medline].
Bhat R, Sharma VK, Deka RC. Otorhinolaryngologic manifestations of leprosy. Int J Dermatol. Jun 2007;46(6):600-6. [Medline].
Motta AC, Komesu MC, Silva CH, et al. Leprosy-specific oral lesions: a report of three cases. Med Oral Patol Oral Cir Bucal. Aug 1 2008;13(8):E479-82. [Medline].
Sehgal VN, Srivastava G, Singh N, Prasad PV. Histoid leprosy: the impact of the entity on the postglobal leprosy elimination era. Int J Dermatol. Jun 2009;48(6):603-10. [Medline].
Batista MD, Porro AM, Maeda SM, et al. Leprosy reversal reaction as immune reconstitution inflammatory syndrome in patients with AIDS. Clin Infect Dis. Mar 15 2008;46(6):e56-60. [Medline].
Menezes VM, Sales AM, Illarramendi X, et al. Leprosy reaction as a manifestation of immune reconstitution inflammatory syndrome: a case series of a Brazilian cohort. AIDS. Mar 13 2009;23(5):641-3. [Medline].
Scollard DM, Joyce MP, Gillis TP. Development of leprosy and type 1 leprosy reactions after treatment with infliximab: a report of 2 cases. Clin Infect Dis. Jul 15 2006;43(2):e19-22. [Medline].
Camacho ID, Valencia I, Rivas MP, Burdick AE. Type 1 leprosy reaction manifesting after discontinuation of adalimumab therapy. Arch Dermatol. Mar 2009;145(3):349-51. [Medline].
Ghorpade A. Ornamental tattoos and skin lesions. Tattoo inoculation borderline tuberculoid leprosy. Int J Dermatol. Jan 2009;48(1):11-3. [Medline].
Trindade MA, Palermo ML, Pagliari C, et al. Leprosy in transplant recipients: report of a case after liver transplantation and review of the literature. Transpl Infect Dis. Feb 2011;13(1):63-9. [Medline].
Ardalan M, Ghaffari A, Ghabili K, Shoja MM. Lepromatous leprosy in a kidney transplant recipient: a case report. Exp Clin Transplant. Jun 2011;9(3):203-6. [Medline].
Vanderborght PR, Pacheco AG, Moraes ME, et al. HLA-DRB1*04 and DRB1*10 are associated with resistance and susceptibility, respectively, in Brazilian and Vietnamese leprosy patients. Genes Immun. Jun 2007;8(4):320-4. [Medline].
Alter A, Alcaïs A, Abel L, Schurr E. Leprosy as a genetic model for susceptibility to common infectious diseases. Hum Genet. Apr 2008;123(3):227-35. [Medline].
Schurr E, Alcaïs A, de Leseleuc L, Abel L. Genetic predisposition to leprosy: A major gene reveals novel pathways of immunity to Mycobacterium leprae. Semin Immunol. Dec 2006;18(6):404-10. [Medline].
Goulart LR, Ferreira FR, Goulart IM. Interaction of TaqI polymorphism at exon 9 of the vitamin D receptor gene with the negative lepromin response may favor the occurrence of leprosy. FEMS Immunol Med Microbiol. Oct 2006;48(1):91-8. [Medline].
Velayati AA, Farnia P, Khalizadeh S, Farahbod AM, Hasanzadh M, Sheikolslam MF. Interferon-gamma receptor-1 gene promoter polymorphisms and susceptibility to leprosy in children of a single family. Am J Trop Med Hyg. Apr 2011;84(4):627-9. [Medline]. [Full Text].
Bhushan P, Sardana K, Koranne RV, Choudhary M, Manjul P. Diagnosing multibacillary leprosy: a comparative evaluation of diagnostic accuracy of slit-skin smear, bacterial index of granuloma and WHO operational classification. Indian J Dermatol Venereol Leprol. Jul-Aug 2008;74(4):322-6. [Medline].
Silva EA, Iyer A, Ura S, et al. Utility of measuring serum levels of anti-PGL-I antibody, neopterin and C-reactive protein in monitoring leprosy patients during multi-drug treatment and reactions. Trop Med Int Health. Dec 2007;12(12):1450-8. [Medline].
Parkash O, Kumar A, Pandey R, Nigam A, Girdhar BK. Performance of a lateral flow test for the detection of leprosy patients in India. J Med Microbiol. Jan 2008;57:130-2. [Medline].
Parkash O, Kumar A, Pandey R, Franken KL, Ottenhoff TH. Detection of Mycobacterium leprae infection employing a combinatorial approach of anti-45 kDa and modified anti-PGL-I antibody detection assays. J Med Microbiol. Aug 2007;56:1129-30. [Medline].
Bang PD, Suzuki K, Phuong le T, Chu TM, Ishii N, Khang TH. Evaluation of polymerase chain reaction-based detection of Mycobacterium leprae for the diagnosis of leprosy. J Dermatol. May 2009;36(5):269-76. [Medline].
Phetsuksiri B, Rudeeaneksin J, Supapkul P, Wachapong S, Mahotarn K, Brennan PJ. A simplified reverse transcriptase PCR for rapid detection of Mycobacterium leprae in skin specimens. FEMS Immunol Med Microbiol. Dec 2006;48(3):319-28. [Medline].
Rothschild BM, Rothschild C. Skeletal manifestations of leprosy: analysis of 137 patients from different clinical settings in the pre- and post-modern treatment eras. J Clin Rheumatol. Aug 2001;7(4):228-37. [Medline].
Gupta SK, Nigam S, Mandal AK, Kumar V. S-100 as a useful auxiliary diagnostic aid in tuberculoid leprosy. J Cutan Pathol. Jul 2006;33(7):482-6. [Medline].
Reddy RR, Singh G, Sacchidanand S, et al. A comparative evaluation of skin and nerve histopathology in single skin lesion leprosy. Indian J Dermatol Venereol Leprol. Nov-Dec 2005;71(6):401-5. [Medline].
World Health Organization. WHO-recommended MDT regimens. World Health Organization. Available at http://www.who.int/lep/mdt/regimens/en/.
Jing Z, Zhang R, Zhou D, Chen J. Twenty five years follow up of MB leprosy patients retreated with a modified MDT regimen after a full course of dapsone mono-therapy. Lepr Rev. Jun 2009;80(2):170-6. [Medline].
Bureau of Primary Health Care. Standard treatment regimens. US Department of Health and Human Services. Health Resources and Services Administration. Available at http://www.hrsa.gov/hansens/clinical/regimens.htm.
Sapkota BR, Shrestha K, Pandey B, Walker SL. A retrospective study of the effect of modified multi-drug therapy in Nepali leprosy patients following the development of adverse effects due to dapsone. Lepr Rev. Dec 2008;79(4):425-8. [Medline].
Balagon MF, Cellona RV, Abalos RM, Gelber RH, Saunderson PR. The efficacy of a four-week, ofloxacin-containing regimen compared with standard WHO-MDT in PB leprosy. Lepr Rev. Mar 2010;81(1):27-33. [Medline].
Duthie MS, Hay MN, Rada EM, et al. Specific IgG antibody responses may be used to monitor leprosy treatment efficacy and as recurrence prognostic markers. Eur J Clin Microbiol Infect Dis. May 5 2011;[Medline].
Fabi SG, Hill C, Witherspoon JN, Boone SL, West DP. Frequency of thromboembolic events associated with thalidomide in the non-cancer setting: a case report and review of the literature. J Drugs Dermatol. Aug 2009;8(8):765-9. [Medline].
Moet FJ, Pahan D, Oskam L, Richardus JH. Effectiveness of single dose rifampicin in preventing leprosy in close contacts of patients with newly diagnosed leprosy: cluster randomised controlled trial. BMJ. Apr 5 2008;336(7647):761-4. [Medline].
Smith WC. Chemoprophylaxis in the prevention of leprosy. BMJ. Apr 5 2008;336(7647):730-1. [Medline].
Rao PS, Sugamaran DS, Richard J, Smith WC. Multi-centre, double blind, randomized trial of three steroid regimens in the treatment of type-1 reactions in leprosy. Lepr Rev. Mar 2006;77(1):25-33. [Medline].
Safa G, Darrieux L, Coic A, Tisseau L. Type 1 leprosy reversal reaction treated with topical tacrolimus along with systemic corticosteroids. Indian J Med Sci. Aug 2009;63(8):359-62. [Medline].
Aires NB, Refkalefsky Loureiro W, Villela MA, Sakai Valente NY, Trindade MA. Sweet's syndrome type leprosy reaction. J Eur Acad Dermatol Venereol. Apr 2009;23(4):467-9. [Medline].
Chauhan S, D'Cruz S, Mohan H, Singh R, Ram J, Sachdev A. Type II lepra reaction: an unusual presentation. Dermatol Online J. Jan 27 2006;12(1):18. [Medline].
Faber WR, Jensema AJ, Goldschmidt WF. Treatment of recurrent erythema nodosum leprosum with infliximab. N Engl J Med. Aug 17 2006;355(7):739. [Medline].
Ramien ML, Wong A, Keystone JS. Severe refractory erythema nodosum leprosum successfully treated with the tumor necrosis factor inhibitor etanercept. Clin Infect Dis. Mar 1 2011;52(5):e133-5. [Medline].
Costa IM, Kawano LB, Pereira CP, Nogueira LS. Lucio's phenomenon: a case report and review of the literature. Int J Dermatol. Jul 2005;44(7):566-71. [Medline].
Crawford CL. No role for thalidomide in the treatment of leprosy. J Infect Dis. Jun 15 2006;193(12):1743-4; author reply 1744-5. [Medline].
Sena CB, Salgado CG, Tavares CM, Da Cruz CA, Xavier MB, Do Nascimento JL. Cyclosporine A treatment of leprosy patients with chronic neuritis is associated with pain control and reduction in antibodies against nerve growth factor. Lepr Rev. Jun 2006;77(2):121-9. [Medline].
Nashed SG, Rageh TA, Attallah-Wasif ES, Abd-Elsayed AA. Intraneural injection of corticosteroids to treat nerve damage in leprosy: a case report and review of literature. J Med Case Reports. Dec 9 2008;2:381. [Medline]. [Full Text].
Rath S, Schreuders TA, Selles RW. Early postoperative active mobilisation versus immobilisation following tibialis posterior tendon transfer for foot-drop correction in patients with Hansen's disease. J Plast Reconstr Aesthet Surg. Feb 19 2009;[Medline].
Shah RK. Tibialis posterior transfer by interosseous route for the correction of foot drop in leprosy. Int Orthop. Dec 2009;33(6):1637-40. [Medline].
Kanaji A, Higashi M, Namisato M, Nishio M, Ando K, Yamada H. Effects of risedronate on lumbar bone mineral density, bone resorption, and incidence of vertebral fracture in elderly male patients with leprosy. Lepr Rev. Jun 2006;77(2):147-53. [Medline].
Pereira HL, Ribeiro SL, Pennini SN, Sato EI. Leprosy-related joint involvement. Clin Rheumatol. Jan 2009;28(1):79-84. [Medline].
Drug resistance in leprosy: reports from selected endemic countries. Wkly Epidemiol Rec. Jun 26 2009;84(26):264-7. [Medline].
Ludwig RJ, Henke U, Wolter M, et al. Persistence of peri-neural granulomas after successful treatment of leprosy. J Eur Acad Dermatol Venereol. Nov 2007;21(10):1414-6. [Medline].
Sales AM, de Matos HJ, Nery JA, Duppre NC, Sampaio EP, Sarno EN. Double-blind trial of the efficacy of pentoxifylline vs thalidomide for the treatment of type II reaction in leprosy. Braz J Med Biol Res. Feb 2007;40(2):243-8. [Medline].
Aráoz R, Honoré N, Cho S, Kim JP, Cho SN, Monot M, et al. Antigen discovery: a postgenomic approach to leprosy diagnosis. Infect Immun. Jan 2006;74(1):175-82. [Medline]. [Full Text].
Barker LP. Mycobacterium leprae interactions with the host cell: recent advances. Indian J Med Res. Jun 2006;123(6):748-59. [Medline].
Chimenos Kustner E, Pascual Cruz M, Pinol Dansis C, Vinals Iglesias H, Rodríguez de Rivera Campillo ME, Lopez Lopez J. Lepromatous leprosy: a review and case report. Med Oral Patol Oral Cir Bucal. Nov 1 2006;11(6):E474-9. [Medline].
Dayal R, Singh SP, Mathur PP, Katoch VM, Katoch K, Natrajan M. Diagnostic value of in situ Polymerase Chain Reaction in leprosy. Indian J Pediatr. Dec 2005;72(12):1043-6. [Medline].
Global leprosy situation, 2006. Wkly Epidemiol Rec. Aug 11 2006;81(32):309-16. [Medline].
Jacobson RR, Krahenbuhl JL. Leprosy. Lancet. Feb 20 1999;353(9153):655-60. [Medline].
Leal AM, Foss NT. Endocrine dysfunction in leprosy. Eur J Clin Microbiol Infect Dis. Jan 2009;28(1):1-7. [Medline].
Moschella SL. An update on the diagnosis and treatment of leprosy. J Am Acad Dermatol. Sep 2004;51(3):417-26. [Medline].
Rai VM, Balachandran C. Necrotic erythema nodosum leprosum. Dermatol Online J. Mar 30 2006;12(3):12. [Medline].
Ramos-e-Silva M, Ribeiro de Castro MC. Mycobacterial infections. In: Bolognia, Jorizzo, Rapini, eds. Dermatology. Vol 1. Philadelphia, Pa: Mosby; 2003:1145-52.
Rinaldi A. The global campaign to eliminate leprosy. PLoS Med. Dec 2005;2(12):e341. [Medline].
Sehgal VN. Spontaneous appearances of papules, nodules, and/or plaques: a prelude to abacillary, paucibacillary, or multibacillary histoid leprosy. Skinmed. May-Jun 2006;5(3):139-41. [Medline].
Walker SL, Lockwood DN. Leprosy. Clin Dermatol. Mar-Apr 2007;25(2):165-72. [Medline].
Yoder LJ, Guerra IE. Hansen's Disease: A Guide to Management in the United States. Carville, La: Hansen's Disease Foundation; 1996:18-22.

