disease leprosy

Signs and Symptoms

Symptoms mainly affect the skin, nerves, and mucous membranes (the soft, moist areas just inside the body’s openings).

The disease can cause skin symptoms such as:A large, discolored lesion on the chest of a person with Hansen’s disease.

A large, discolored lesion on the chest of a person with Hansen’s disease.

  • Discolored patches of skin, usually flat, that may be numb and look faded (lighter than the skin around)
  • Growths (nodules) on the skin
  • Thick, stiff or dry skin
  • Painless ulcers on the soles of feet
  • Painless swelling or lumps on the face or earlobes
  • Loss of eyebrows or eyelashes

Symptoms caused by damage to the nerves are:

  • Numbness of affected areas of the skin
  • Muscle weakness or paralysis (especially in the hands and feet)
  • Enlarged nerves (especially those around the elbow and knee and in the sides of the neck)
  • Eye problems that may lead to blindness (when facial nerves are affected)

Enlarged nerves below the skin and dark reddish skin patch overlying the nerves affected by the bacteria on the chest of a patient with Hansen’s disease. This skin patch was numb when touched.

Enlarged nerves below the skin and dark reddish skin patch overlying the nerves affected by the bacteria on the chest of a patient with Hansen’s disease. This skin patch was numb when touched.

Symptoms caused by the disease in the mucous membranes are:

  • A stuffy nose
  • Nosebleeds

Since Hansen’s disease affects the nerves, loss of feeling or sensation can occur. When loss of sensation occurs, injuries such as burns may go unnoticed. Because you may not feel the pain that can warn you of harm to your body, take extra caution to ensure the affected parts of your body are not injured.

If left untreated, the signs of advanced leprosy can include:

  • Paralysis and crippling of hands and feet
  • Shortening of toes and fingers due to reabsorption
  • Chronic non-healing ulcers on the bottoms of the feet
  • Blindness
  • Loss of eyebrows
  • Nose disfigurement

Other complications that may sometimes occur are:

  • Painful or tender nerves
  • Redness and pain around the affected area
  • Burning sensation in the skin

Key facts

  • Leprosy is a chronic infectious disease caused by a bacillus, Mycobacterium leprae. M leprae multiplies slowly and the incubation period of the disease, on average, is 5 years. Symptoms may occur within 1 year but can also take as long as 20 years or even more.
  • Leprosy mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract, and the eyes. The disease is curable with multidrug therapy.
  • Leprosy is likely transmitted via droplets, from the nose and mouth, during close and frequent contact with untreated cases. Untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs, and eyes.
  • There were 127558 new leprosy cases detected globally in 2020, according to official figures from 139 countries from the 6 WHO Regions. This includes 8 629 children below 15 years. The new case detection rate among child population was recorded at 4.4 per million child population.
  • Among the new cases 7 198 new cases were detected with grade2 disabilities (G2D) and the new G2D rate was recorded at 0.9 per million population
  • At the end of the year 2020, the prevalence was 129 389 cases on treatment and prevalence rate corresponds to 16.7 per million population.
  • The COVID 19 pandemic has disrupted programme implementation and a reduction in new case detection by 37% in 2020 compared with 2019


Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an acid-fast, rod-shaped bacillus. The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract, and the eyes. Leprosy is curable and treatment in the early stages can prevent disability.

Brief history and treatment

Leprosy is an age-old disease, described in the literature of ancient civilizations. Throughout history, people afflicted have often been ostracized by their communities and families.

Although leprosy was managed differently in the past, the first breakthrough occurred in the 1940s with the development of the medicine dapsone. The duration of treatment lasted many years, often a lifetime, making compliance difficult. In the 1960s, M. leprae started to develop resistance to dapsone, the only known anti-leprosy medicine at that time. In the early 1960s, rifampicin and clofazimine were discovered and subsequently added to the treatment regimen, which was later labelled as multidrug therapy (MDT).

In 1981, WHO recommended MDT. The currently recommended MDT regimen consists of medicines: dapsone, rifampicin and clofazimine. This treatment lasts six months for pauci-bacillary and 12 months for multi-bacillary cases. MDT kills the pathogen and cures the patient.

Since 1981 WHO has provided MDT free of cost. Free MDT was initially funded by The Nippon Foundation, and since 2000 it is donated through an agreement with Novartis until 2025.

More than 16 million leprosy patients have been treated with MDT over the past 20 years. A general reduction in new cases, though gradual is observed in several countries. The new cases reduced to 202 256 in 2019.  Several countries reported less number cases, including 45 countries reported zero leprosy cases.

WHO response

In 2018, WHO reviewed available evidence on key issues related to elimination of leprosy and developed WHO guidelines for the diagnosis, treatment and prevention of leprosy 2018, recommending  three-drug regimen (rifampicin, dapsone and clofazimine)  to both pauci-bacillary and multibacillary types of leprosy. The guidelines also introduced prevention of leprosy through single dose of rifampicin for eligible familial and social contacts.

After a detailed consultations with countries, experts in leprosy, partners and persons affected by leprosy WHO released Towards Zero Leprosy -– Global Leprosy (Hansen’s disease) Strategy 2021‒-2030  in line with NTD road map 2030 in April 2021.

The strategy is published in English and translated versions into French, Portuguese, Spanish and Russian languages are made available for reaching wider global audience.


Long term vision

Zero leprosy: zero infection and disease, zero disability, zero stigma and discrimination


Elimination of leprosy (defined as interruption of transmission) 

Global targets for 2030

  • 120 countries with zero new autochthonous cases
  • 70% reduction in annual number of new cases detected
  • 90% reduction in rate per million population of new cases with grade-2 disability (G2D)
  • 90% reduction in rate per million children of new child cases with leprosy

Strategic pillars and key components

1: Implement integrated, country-owned zero leprosy roadmaps in all endemic countries

  • Political commitment with adequate resources for leprosy in integrated context
  • National partnerships for zero leprosy and zero leprosy roadmaps engaging all stakeholders 
  • Capacity building in the healthcare system for quality services
  • Effective surveillance and improved data management systems
  • Monitoring of antimicrobial resistance (AMR) and adverse drug reactions

2: Scale up leprosy prevention alongside integrated active case detection

  • Contact tracing for all new cases
  • Preventive chemotherapy scaled up
  • Integrated active case-finding in targeted populations
  • Existing and potential new vaccines

3: Manage leprosy and its complications and prevent new disability

  • Early case detection, accurate diagnosis and prompt treatment
  • Access to comprehensive, well-organized referral facilities
  • Diagnosis and management of leprosy reactions, neuritis and disabilities
  • Monitoring, support and training in self-care 
  • Mental well-being through psychological first aid and therapeutic counselling

4: Combat stigma and ensure human rights are respected

  • Adoption of Principles and Guidelines for elimination of discrimination against persons affected by leprosy and their family members
  • Inclusion of organizations and networks of persons affected by leprosy
  • Amendment of discriminatory laws
  • Interventions and processes to reduce and monitor leprosy-related stigma in communities
  • Access to social support and rehabilitation


The strategy includes a set of research priorities of key importance for this strategic period. Global and national investment in research is essential to achieving zero leprosy.

Measuring progress towards reaching the targets of Global Leprosy Strategy 2021-2030

Indicator2019* (Reported)2023 (Milestone)2025 (Milestone)2030(Milestone)
Number of countries with zero new autochthonous cases3475 (39%)95 (49%)120 (62%)
Number of new cases detected (disaggregated by sex and age)202,256148,000123,50062,500
Rate (per < 1/million population) of new cases with G2D1.40.920.680.12
Rate (per million children) of new autochthonous child cases with leprosy7.835.664.240.77

*Annual leprosy Data of 2019 are considered as baseline for monitoring progress towards reaching of targets of NTD Roadmap 2030 and Global Leprosy Strategy 2021-2030. 

In 2020, WHO brought out a Leprosy/Hansen Disease management of reactions/prevention of disabilities; a published the technical guide – 2020  to provide hands-on guidance to health workers to diagnose early and manage Lepra reactions, conditions might occur as a result of the host’s immune response to the infecting organism, M leprae. These intermittent and recurring inflammatory episodes are known as leprosy reactions. These reactions might occur in as many as 50% of cases. Reactions if left unmanaged in most cases lead to permanent, progressing and disfiguring disabilities.  

The objective of this Technical Guidance document is to review current management practices for leprosy reactions and neuritis and to describe ways in which they can be improved, so that national programmes can achieve their goals of preventing and minimizing disability due to leprosy.

WHO in 2020, brought out a technical guide on: Leprosy Hansen disease contact tracing and post-exposure prophylaxis – 2020.   The objective of the technical guide is to advise countries and programmes on how to implement contact screening and chemoprophylaxis with single-dose rifampicin. The contents are logically ordered: counselling and obtaining consent, identification and listing of index case, listing of contacts, tracing of contacts, screening of contacts, administration of prophylactic drugs. Managerial aspects to undertake contact screening and chemoprophylaxis are also elaborated, including planning, training, supervision, and drug management.

The Global Leprosy Strategy 2021–2030 guides the countries to accelerate progress towards zero leprosy, in line with the Sustainable Development Goals. Optimization of existing tools, such as for contact-tracing, active case-finding, post-exposure prophylaxis with single-dose rifampicin and provision of MDT services are critical activities to interrupt the transmission. The gains must be sustained to ensure elimination by 2030. 

Although the COVID-19 pandemic disrupted health services in general, it provided a window to strengthen digital health initiatives for diagnosis, referral, monitoring and training staff in several countries. 

WHO has developed e-learning modules that aim to enhance knowledge and skills of staff at all levels on topics ranging from suspected referrals and diagnosis to the treatment of leprosy and management of disabilities. 

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