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Disease Information

Summary

Leprosy, also called Hansen disease, is a disorder known since ancient times. It is caused by bacteria called Mycobacterium leprae and is contagious, which means that it can be passed from person to person. It is usually contracted by breathing airborne droplets from affected individuals' coughs and sneezes, or by coming into contact with their nasal fluids. However, it is not highly transmissible, and approximately 95 percent of individuals who are exposed to Mycobacterium leprae never develop leprosy. The infection can be contracted at any age, and signs and symptoms can take anywhere from several months to 20 years to appear. Leprosy affects the skin and the peripheral nerves, which connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, and heat. Most affected individuals have areas of skin damage (cutaneous lesions) and problems with nerve function (peripheral neuropathy); however, the severity and extent of the problems vary widely. Leprosy occurs on a spectrum, in which the most severe form is called multibacillary or lepromatous, and the least severe form is called paucibacillary or tuberculoid. Patterns of signs and symptoms intermediate between these forms are sometimes called borderline forms. Multibacillary leprosy usually involves a large number of cutaneous lesions, including both surface damage and lumps under the skin (nodules). The moist tissues that line body openings such as the eyelids and the inside of the nose and mouth (mucous membranes) can also be affected, which can lead to vision loss, destruction of nasal tissue, or impaired speech. Some affected individuals have damage to internal organs and tissues. The nerve damage that occurs in multibacillary leprosy often results in a lack of sensation in the hands and feet. Repeated injuries that go unnoticed and untreated because of this lack of sensation can lead to reabsorption of affected fingers or toes by the body, resulting in the shortening or loss of these digits. Paucibacillary leprosy typically involves a small number of surface lesions on the skin. There is generally loss of sensation in these areas, but the other signs and symptoms that occur in multibacillary leprosy are less likely to develop in this form of the disorder. In any form of leprosy, episodes called reactions can occur, and can lead to further nerve damage. These episodes can include reversal reactions, which involve pain and swelling of the skin lesions and the nerves in the hands and feet. People with the more severe forms of leprosy can develop a type of reaction called erythema nodosum leprosum (ENL). These episodes involve fever and painful skin nodules. In addition, painful, swollen nerves can occur. ENL can also lead to inflammation of the joints, eyes, and the testicles in men. Leprosy has long been stigmatized because of its infectious nature and the disfigurement it can cause. This stigma can cause social and emotional problems for affected individuals. However, modern treatments can prevent leprosy from getting worse and spreading to other people. While the infection is curable, nerve and tissue damage that occurred before treatment is generally permanent.

About Leprosy

Many rare diseases have limited information. Currently, GARD aims to provide the following information for this disease:

  • Symptoms:May start to appear at any time in life.
  • Cause:This disease is caused by harmful bacteria.
  • Organizations:Contact a GARD Information Specialist to help search for patient organizations dedicated to this rare disease.
  • Categories:Infectious diseases(Infectious diseases are caused by bacteria, viruses, fungi, or parasites entering the body, multiplying, and spreading illness.)Neurological diseases(Neurological diseases affect the brain, spinal cord, cranial nerves, autonomic nerves, or other peripheral nerves.)

Resource(s) for Medical Professionals and Scientists on This Disease:

  • MONDO provides GARD with information for this disease.
  • Orphanet provides GARD with information for this disease.

Resource(s) for Medical Professionals and Scientists on This Disease:

  • MONDO provides GARD with information for this disease.
  • Orphanet provides GARD with information for this disease.

About Leprosy

Many rare diseases have limited information. Currently, GARD aims to provide the following information for this disease:

  • Symptoms:May start to appear at any time in life.
  • Cause:This disease is caused by harmful bacteria.
  • Organizations:Contact a GARD Information Specialist to help search for patient organizations dedicated to this rare disease.
  • Categories:Infectious diseases(Infectious diseases are caused by bacteria, viruses, fungi, or parasites entering the body, multiplying, and spreading illness.)Neurological diseases(Neurological diseases affect the brain, spinal cord, cranial nerves, autonomic nerves, or other peripheral nerves.)

Causes

What Causes This Disease?

Bacterial Infection

This disease is caused by harmful bacteria that enter the body. Bacteria are single-celled organisms that release toxins as they multiply. Bacterial infections can be contagious. You may get a bacterial infection when you come into close contact with contaminated surfaces, eat or drink contaminated food or water, or are exposed to other people who can spread the bacteria. Often, bacterial infections enter your body through your mouth, nose, eyes, or a cut in your skin. Learn more about bacterial infectious diseases through the National Library of Medicine.

Bacterial Infection

This disease is caused by harmful bacteria that enter the body. Bacteria are single-celled organisms that release toxins as they multiply. Bacterial infections can be contagious. You may get a bacterial infection when you come into close contact with contaminated surfaces, eat or drink contaminated food or water, or are exposed to other people who can spread the bacteria. Often, bacterial infections enter your body through your mouth, nose, eyes, or a cut in your skin. Learn more about bacterial infectious diseases through the National Library of Medicine.

When Do Symptoms of Leprosy Begin?

Symptoms of this disease may start to appear at any time in life.

The age symptoms may begin to appear differs between diseases. Symptoms may begin in a single age range, or during several age ranges. The symptoms of some diseases may begin at any age. Knowing when symptoms may have appeared can help medical providers find the correct diagnosis.
  1. Prenatal Selected
    Before Birth
  2. Newborn Selected
    Birth-4 weeks
  3. Infant Selected
    1-23 months
  4. Child Selected
    2-11 years
  5. Adolescent Selected
    12-18 years
  6. Adult Selected
    19-65 years
  7. Older Adult Selected
    65+ years
Symptoms may start to appear at any time in life.
This information comes from Orphanet

Symptoms

You may have one or more symptoms, and they may be mild or severe. Having some or all of these symptoms does not mean you have this disease. Only a health care provider can diagnose you.

Common

Many people have these, but not everyone.

  • Abnormal autonomic nervous system physiology
  • Acral ulceration
  • Acute episodes of neuropathic symptoms
  • Decreased ability to sweat (Hypohidrosis)
  • Dissociated sensory loss
  • Enlarged peripheral nerve
  • Entrapment neuropathy
  • Hyperkeratosis
  • Hypopigmented macule
  • Impaired temperature sensation
  • Muscle degeneration (Skeletal muscle atrophy)
  • Peripheral neuropathy
  • Pins and needles feeling (Paresthesia)
  • Skin nodule
  • Sparse body hair

Uncommon

Some people have these, but most people do not.

  • Abnormal bone marrow cell morphology
  • Abnormal seventh cranial physiology
  • Abnormality of facial skeleton (Abnormal facial skeleton morphology)
  • Abnormality of the liver
  • Abnormality of the spleen
  • Abnormality of the upper respiratory tract
  • Absent eyebrow
  • Adrenal abnormalities (Abnormality of the adrenal glands)
  • Autoamputation of digits
  • Blindness
  • Bloody nose (Epistaxis)
  • Constrictive median neuropathy
  • Corneal perforation
  • Corneal ulceration
  • Decreased corneal sensation
  • Dysesthesia
  • Enlarged male breast (Gynecomastia)
  • Facial shape deformation
  • Foot drop (Foot dorsiflexor weakness)
  • Glaucoma
  • Hair loss (Alopecia)
  • High stepping (Steppage gait)
  • Inflammation of iris (Iritis)
  • Loss of eyelashes
  • Muscle weakness
  • Paralytic lagophthalmos
  • Penetrating foot ulcers
  • Testicular mass
  • Urticarial plaque
  • Uveitis
  • Verrucous papule
This information comes from the Human Phenotype Ontology (HPO)

Navigating Health Care Decisions

On average, it can take more than six years to receive an accurate diagnosis. Many primary care providers (PCPs) may not be familiar with rare diseases, and patients often need to visit multiple specialists or seek second opinions to get answers.

If a diagnosis remains unclear, visiting a multidisciplinary care center or university hospital may help. These centers bring together teams of specialists who can work together to evaluate symptoms and coordinate a diagnosis. This team-based approach is also helpful after a diagnosis, when managing care for rare diseases.

Because only about 5% of rare diseases have FDA-approved treatments, finding the right healthcare team to manage your symptoms and overall health is essential. People living with rare diseases often face challenges such as delayed diagnosis, limited treatment options, and difficulty accessing knowledgeable providers. Building a care team that understands your needs can make a significant difference in your quality of life.

Your Health Care Team

Why is building the right health care team important?

Building the right health care team is key to the diagnosis, treatment, and management of your long-term health journey living with a rare disease. Start by choosing a primary care provider (PCP). Your PCP will be your main point of contact and help coordinate care with other medical professionals. Your PCP may order tests or refer you to specialists. To find a PCP near you, use the Medicare provider search tool and enter your location and “Primary Care Provider.”

Seeing multiple specialists is important for people with rare diseases because these conditions often affect many parts of the body and require care from doctors with different expertise. Most primary care providers may not be familiar with rare diseases, so involving specialists can lead to a more accurate diagnosis and better care. A coordinated team approach ensures that all symptoms are addressed and that care is well-managed. It can also connect patients with the latest research or treatment options.

A PCP that specializes in the care of children is called a pediatrician. Use this tool by the American Academy of Pediatrics to find a pediatrician in your area by inputting your location.

These specialists may help in the diagnosis, management, and treatment of Leprosy:

Neurologists are doctors with specialized training in diagnosing and treating conditions that affect the brain, spinal cord, and nerves. These parts of the nervous system help control how the body moves, feels, and thinks. Neurologists often care for people with seizures, memory problems, muscle weakness, movement disorders, and inherited conditions such as muscular dystrophies. To better understand a person's symptoms, neurologists may use imaging tests that show the brain or spine, or tests that measure the brain’s electrical activity.

You may want to consider bringing a copy of your medical history and a list of any medications to your appointment.

Ask your primary care provider for a referral or use this directory provided by the American Board of Psychiatry and Neurology to find a specialist. 
Infectious disease specialists are doctors with advanced training in diagnosing and treating infections caused by bacteria, viruses, fungi, or parasites. They often help manage complex, persistent, or rare infections that are difficult to diagnose or treat. These specialists may also have experience with infections linked to rare diseases, weakened immune systems, or recent travel to areas where certain infections are more common. They use a range of tools including specialized lab testing of blood, tissue, or fluids to identify the exact cause of an infection. Treatments may involve medications taken by mouth, applied to the skin, or delivered through an injection or directly into a vein.

You may want to consider bringing a copy of your medical history and a list of any medications to your appointment.

Ask your primary care provider for a referral or use this directory provided by Medicare to search for a specialist. Search using the keywords “Infectious Disease.”

Multidisciplinary Care Centers

Is It Time to Get a Second Opinion or Specialized Evaluation?

If you've visited your PCP, met with specialists, and undergone the recommended tests, but are still searching for a diagnosis, it may be time to visit an academic medical center or, for pediatric patients, a children's hospital. Academic medical centers and children's hospitals, often called multidisciplinary care centers, typically bring together specialists from different fields to work together on complex cases like rare diseases.

Multidisciplinary care centers may offer more coordinated care and be involved in clinical research, which may help reduce the time to diagnosis and provide access to emerging diagnostic tools. Specialists at these centers may have a deeper understanding of rare diseases and serve as a resource when you'd like a second opinion, particularly when test results or treatment plans are not delivering expected results.

Find hospitals that may partner with medical schools and programs in your area. 

Children’s hospitals and large teaching hospitals may also offer dedicated specialists and programs for pediatric patients with undiagnosed or rare diseases. These programs bring pediatric experts together in one place and may provide more coordinated care for your child.

Search for children's or university hospitals in your area.

Rare Disease Experts

How can you find a rare disease expert?

If a diagnosis, care management, or treatment plan remains unclear despite extensive efforts by your PCP and specialists, it may be time to find a rare disease expert for your disease, if available. A rare disease expert is a medical provider that has knowledge or training on specific rare disease(s), but there may only be a few experts in your state, region, or country. Rare disease experts may work at large research or teaching hospitals, sometimes called centers of excellence. Centers of Excellence commit to sharing knowledge and best practices that can lead to improved care and treatment for individuals living with a rare disease. 

You can also contact a GARD Information Specialist for help finding experts, centers of excellence, or clinics that focus on your disease.
You can ask your care providers for help finding an expert or use directory tools to search for experts near you. The following organization(s) may maintain a list of experts or expert centers for people living with Leprosy:

Find Your Community

How can patient organizations help?

Patient organizations can help patients and families connect. They build public awareness of the disease and are a driving force behind research to improve patients' lives. They may offer online and in-person resources to help people live well with their disease. Many collaborate with medical experts and researchers.

Services of patient organizations differ, but may include:

  • Ways to connect to others and share personal stories
  • Easy-to-read information
  • Up-to-date treatment and research information
  • Patient registries
  • Lists of specialists or specialty centers
  • Financial aid and travel resources


Please note: GARD provides organizations for informational purposes only and not as an endorsement of their services. Contact a GARD Information Specialist for more information on organizations that may be dedicated to this disease. Please contact an organization directly if you have questions about the information or resources it provides.


View GARD's criteria for including patient organizations, which can be found under the FAQs on our About GARD page. Request an update or to have your organization added to GARD. 

Patient Organizations

3 Organizations

Resolve: The National Infertility Association

People With

Infertility

Helpful Links
Country

United States

The Foundation for Peripheral Neuropathy

People With

Peripheral neuropathy

Helpful Links
Country

United States

Neuropathy Action Foundation

People With

Peripheral neuropathy

Country

United States

OrganizationPeople WithHelpful LinksCountry
Resolve: The National Infertility AssociationInfertilityList of ExpertsUnited States
The Foundation for Peripheral NeuropathyPeripheral neuropathyList of Experts
Research Registry		United States
Neuropathy Action FoundationPeripheral neuropathyUnited States

Participate in Research

Clinical studies are a part of clinical research and play an important role in medical advances for rare diseases. Through clinical studies, researchers may ultimately uncover better ways to treat, prevent, diagnose, and understand human diseases.

What Are Clinical Studies?

Clinical studies are medical research involving people as participants. There are two main types of clinical studies:

  1. Clinical trials determine if a new test or treatment for a disease is effective and safe by comparing groups receiving different tests/treatments.
  2. Observational studies involve recording changes over time among a specific group of people in their natural settings.

Learn more about clinical trials from this National Institutes of Health webpage.

Why Participate in Clinical Studies?

People participate in clinical trials for many reasons. People with a disease may participate to receive the newest possible treatment and additional care from clinical study staff as well as to help others living with the same or a similar disease. Healthy volunteers may participate to help others and to contribute to moving science forward.

To find the right clinical study we recommend you consult your doctors, other trusted medical professionals, and patient organizations. Additionally, you can use ClinicalTrials.gov to search for clinical studies by disease, terms, or location.

What if There Are No Available Clinical Studies?

ResearchMatch helps connect people interested in research studies  with researchers from top medical centers across the United States. Anyone from the U.S. can register with this free program funded by NIH. Researchers from participating institutions use the database to search for and invite patients or healthy volunteers who meet their study criteria to participate.

Why may you want to consider joining the All of Us Research Program?

The All of Us Research Program is inviting 1 million people from all backgrounds across the U.S. to help build one of the most diverse health databases in history. Researchers will use the data to learn how our biology, lifestyle, and environment affect health. This may one day help them find ways to treat and prevent diseases.

ClinicalTrials.gov, an affiliate of NIH, provides current information on clinical research studies in the United States and abroad. Talk to a trusted doctor before choosing to participate in any clinical study. We recommend checking this site often and searching for studies with related terms/synonyms to improve results.
Search ClinicalTrials.gov for this disease.
GARDGenetic and Rare Diseases
Information Center
Contact a GARD Information Specialist if you need help finding more information on this rare disease or available clinical studies. Please note that GARD cannot enroll individuals in clinical studies.
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Sources & References

Last Updated: September 2026