Overview
Buruli ulcer is a skin infection caused by bacteria that release a toxin destroying skin and the tissue beneath it. It usually begins as a painless lump or swelling, and because it does not hurt and causes no fever, people often wait.
WHO states that without treatment the lump will break open into an ulcer within about four weeks. Caught early it is cured with eight weeks of tablets. Caught late it can destroy large areas of skin and leave lasting disability.
Disease Summary
- Category
- Infectious Disease
- Cause
- Mycobacterium ulcerans
- Transmission
- Not fully known
- Body System
- Skin
- Preventable
- No
- Curable
- Yes
Symptoms
Common Symptoms
The striking feature of Buruli ulcer is what is absent. WHO states the disease progresses with no pain and no fever, which is why people present late.
A Painless Lump
WHO states the disease often starts as a painless swelling, or nodule, under the skin.
A Painless Hardened Area of Skin
WHO describes a large painless area of firm, thickened skin, called a plaque.
Painless Swelling of a Limb or the Face
WHO describes diffuse painless swelling of the legs, arms or face.
No Pain and No Fever
WHO notes explicitly that the disease progresses without pain or fever. This absence is the reason for late presentation.
Breaking Open Within About Four Weeks
WHO states that without treatment the lump, plaque or swelling will ulcerate within 4 weeks.
Ulcers on the Arms and Legs
WHO records 55% of lesions on the lower limbs, 35% on the upper limbs and 10% elsewhere on the body.
Destruction of Skin and the Tissue Beneath
The toxin kills tissue, so the ulcer often has undermined edges and is larger beneath the skin than it appears.
Bone Involvement
WHO notes that bone is occasionally affected, which causes deformity.
Danger Signs
Seek urgent medical attention immediately if any of the following symptoms develop.
A Lesion Larger Than 15 Centimetres
WHO classifies these as the most severe category, and tracks how many people arrive with lesions this large as a measure of delay.
Pain, Swelling or Deformity Over a Bone or Joint
WHO includes bone and joint involvement in the most severe category.
A Lesion Crossing a Joint
These carry a high risk of permanent stiffness, and physiotherapy needs to begin early.
Extensive Swelling of the Face
Facial lesions are both functionally and socially serious and need specialist care.
A Buruli Lesion in Someone Living With HIV
WHO states that HIV infection makes clinical progression more aggressive and results in poorer treatment outcomes.
Diagnosis
Clinical Diagnosis by a Trained Health Worker
WHO states that experienced health professionals in endemic areas can make a reliable clinical diagnosis, and that training is essential.
Categorising the Lesion at Diagnosis
WHO grades lesions as under 5 centimetres, between 5 and 15 centimetres, or over 15 centimetres including disseminated forms. The category guides treatment and measures how early the case was found.
Mapping Where the Lesion Is
Recording the site supports pattern recognition, since the great majority of lesions are on the limbs.
Deliberately Excluding Other Causes of Leg Ulcers
WHO warns health workers to be careful with lower leg lesions, to avoid confusing Buruli ulcer with ulcers caused by diabetes or poor circulation.
Laboratory Confirmation
WHO’s control strategy specifies confirmation by a molecular test at national level, and tracks the proportion of cases that are laboratory confirmed.
Laboratory Tests
Molecular Test for the Bacteria
WHO lists this first among its four standard confirmation methods and specifies it as the method for national-level confirmation. It is the most sensitive and specific test available.
Direct Microscopy
A positive result supports the diagnosis. A negative result does not exclude it, because sensitivity is limited.
Histopathology
Shows the characteristic pattern of tissue destruction. WHO lists it among the standard confirmation methods.
Culture
Confirms living bacteria but is far too slow to guide the start of treatment.
HIV Test
WHO states HIV co-infection makes progression more aggressive and outcomes worse, so knowing the status changes management.
Treatment
Combination Antibiotics
WHO recommends a combination of rifampicin and clarithromycin taken by mouth for 8 weeks. This kills the bacteria and stops the toxin destroying more tissue. Early cases are cured with antibiotics alone.
Wound Care
WHO calls wound care an essential part of case management. Good dressing practice prevents secondary infection and speeds healing.
Surgery
WHO states surgery, mainly removal of dead tissue and skin grafting, is used primarily to speed the healing of extensive lesions. It supplements antibiotics rather than replacing them.
Physiotherapy
WHO states physiotherapy is needed in severe cases to prevent disability, and that it begins at diagnosis rather than after healing.
Rehabilitation and Psychosocial Support
WHO includes mental health support and social rehabilitation for affected people and their families within the control strategy.
Prevention
Recognise that there is no primary prevention yet
WHO states there are currently no primary preventive measures for Buruli ulcer, because the mode of transmission is still unknown.
Early detection, which is the operative prevention
WHO states that early detection and antibiotic treatment are the cornerstones of the control strategy. This prevents disability rather than infection.
Community awareness of the painless lump
Teaching communities that a painless swelling matters is what brings people in before the lesion breaks open.
Training community health workers and volunteers
WHO’s strategy includes training community health workers and village volunteers to find cases early.
Strengthening laboratory confirmation
WHO set up a laboratory network for Africa in 2019 to strengthen molecular confirmation in endemic countries.
Free antibiotic supply
WHO supplies antibiotics to endemic countries so that cost does not delay treatment.
Risk Factors
Children in Endemic African Communities
WHO Regional Office for Africa reports that nearly half of people affected in Africa are children under 15.
- Children in endemic rural communities
- Children whose painless lump is not recognised as serious
- Children in areas without nearby diagnostic services
- The high proportion of child cases indicates ongoing transmission where they live
People in Remote Rural Areas
WHO notes that reported figures underestimate the true burden because the disease affects isolated, poor rural populations.
- Communities far from a health facility
- Areas with no surveillance at all
- Communities with limited awareness of the disease
- People for whom travel to a treatment centre is costly
People Living With HIV
WHO states that HIV co-infection makes progression more aggressive and outcomes worse.
- People with untreated or poorly controlled HIV
- This group needs earlier detection and closer follow-up
- WHO has published separate guidance on managing the two together
- Testing for HIV is part of assessing a Buruli lesion
Complications
Large Destructive Ulcers
WHO states that without treatment the lesion will ulcerate within about four weeks, and the most severe category exceeds 15 centimetres.
Bone Destruction and Deformity
WHO states that bone is occasionally affected, causing deformity.
Permanent Disfigurement
WHO states that Buruli ulcer can lead to permanent disfigurement and long-term disability.
Joint Stiffness and Loss of Function
Lesions crossing joints can leave lasting contractures, which is why physiotherapy starts at diagnosis.
Stigma and Loss of Livelihood
WHO Regional Office for Africa links late treatment directly to long-term disability, stigma and the economic burden that follows.
Worse Outcomes With HIV
WHO states that HIV co-infection results in more aggressive progression and poorer treatment outcomes.
When to Seek Medical Care
Any Painless Lump or Swelling in an Endemic Area
This is the single most important reason to present, and the point at which treatment is simplest.
Before the Lesion Breaks Open
WHO states the lesion will ulcerate within about four weeks, so the window for the simplest treatment is short.
A Skin Ulcer That Is Not Healing
WHO warns against assuming a lower leg ulcer is caused by diabetes or poor circulation without considering Buruli ulcer.
Loss of Movement at a Joint
Physiotherapy begun early prevents most permanent stiffness.
A Buruli Lesion in Someone Living With HIV
Both conditions need managing together and the lesion is likely to progress faster.
Prognosis
Early Cases Are Cured With Tablets Alone
WHO states that early detection is critical to complete cure with combined antibiotics, using an eight-week oral course.
Late Presentation Drives Disability
WHO states that without early treatment Buruli ulcer can lead to long-term disability, and uses the proportion of large lesions at diagnosis as a programme indicator.
Case Numbers Have Fallen Substantially
WHO Regional Office for Africa reports a reduction of more than 70% in reported cases over the past two decades.
HIV Co-Infection Worsens the Outlook
WHO states that HIV infection results in more aggressive progression and poorer treatment outcomes.
Differential Diagnosis
Ulcers From Diabetes or Poor Circulation
WHO warns specifically about this confusion on the lower leg. These ulcers are usually painful and come with other signs of diabetes or vascular disease.
Cutaneous Leishmaniasis
Also causes a chronic tropical ulcer, and is separated by finding a different parasite rather than these bacteria.
Tropical Phagedenic Ulcer
Another chronic tropical skin ulcer, separated by the painless character of Buruli ulcer and by molecular testing.
Boils, Insect Bites and Lipomas
WHO notes that early nodules may be confused with all of these. The Buruli nodule is painless, causes no fever, and progresses to ulceration within about four weeks.
Tuberculosis of the Lymph Nodes
Can produce a chronic discharging swelling, and is separated by specific testing.
References
World Health Organization: Buruli ulcer
WHO fact sheet on cause, presentation, categories, diagnosis and treatment.
WHO Regional Office for Africa: Buruli ulcer
Regional burden, the proportion of cases in children and access to free treatment.
World Health Organization: Buruli ulcer objective and strategy for control and research
WHO control strategy, programme indicators and the place of disability prevention.
CDC: Buruli ulcer
Overview of the infection and where it occurs.
Frequently Asked Questions
How do people catch Buruli ulcer?
Nobody knows yet. WHO states plainly that the exact mode of transmission is still unknown. Because of this there are no primary preventive measures, and WHO names understanding transmission as one of its research priorities.
Is Buruli ulcer painful?
Usually not, and that is the danger. WHO describes it beginning as a painless lump, a painless hardened patch of skin, or painless swelling of a limb or the face, and states it progresses with no pain and no fever. Without treatment it breaks open within about four weeks.
Can it be cured without surgery?
Often yes, if it is caught early. WHO recommends a combination of rifampicin and clarithromycin taken by mouth for 8 weeks. Surgery, mainly removal of dead tissue and skin grafting, is used primarily to speed the healing of extensive lesions.
Who gets Buruli ulcer?
In Africa, mostly children. WHO Regional Office for Africa states that more than 90% of global cases occur in Africa, where nearly half of those affected are children under 15. The pattern is different elsewhere, with a much older average age in Australia.
Does treatment cost anything?
WHO Regional Office for Africa states that WHO provides antibiotics to endemic countries so that treatment is free of charge for all patients. Costs for wound care, surgery and transport may still apply, so ask at the treatment centre.