Leprosy – or Hansen’s disease – has been known and feared since biblical times.
Even today, the word “leprosy” carries significant stigma, despite the fact that leprosy is not easy to catch and rarely disfiguring with proper diagnosis and treatment.1
Most clinicians associate leprosy with skin lesions and a loss of sensation.
But a recent review of leprosy in the journal PAIN discusses how acute and chronic pain are major symptoms of leprosy. Acute pain may be a presenting symptom, even before skin lesions develop, and may persist even after treatment. 2
Leprosy in America
“Most clinicians in America will never treat a case of leprosy. Like its cousin tuberculosis, leprosy may be easy to miss if you don’t think of it,” said James Cook, MD, professor of infectious disease at Loyola University Medical Center in Maywood, Illinois.
According to the U.S. Department of Health and Human Services, there are about 6,500 active cases of leprosy in the United States.
Although most cases are transmitted by contact with nasal secretions from an infected person, recent research indicates that armadillos may also be a source of infection in the southern United States.1
Worldwide, 80% of leprosy cases are diagnosed in India, Indonesia, Myanmar, Brazil, and Nigeria. 3
Leprosy is a chronic infection caused by the bacteria Mycobacterium leprae.
Leprosy is common in areas of the world with a warm, wet climate. Symptoms and course of the disease depend on the body’s immune response and can range from mild tuberculoid type to severe lepromatous type. 2,3
The infection primarily invades the skin and peripheral nervous system.2
In most patients, the first symptom is numbness, followed by hypopigmented skin lesions. The disease responds very well to treatment with standard antibiotics, and patients become noninfectious after the first few doses.1
Diagnosis can be difficult because the bacteria are hard to find, and the incubation period may last up to 40 years. 3
“The bacteria are almost impossible to grow in a culture. They may be seen in a skin biopsy using special stains. PCR diagnosis is now available at special labs. Prognosis is good with treatment, but patients need to adhere to medications for a long time,” said Cook.
Leprosy and Pain
The review in PAIN found 86 studies of pain in leprosy.
They found that acute pain may be a presenting symptom due to nerve inflammation. And if inflammation causes nerve damage, it may be considered acute neuropathic pain.
Chronic neuropathic pain was found in 11 to 66% of patients, according to the studies reviewed. Mixed inflammatory and& neuropathic pain syndromes were also common. 2
“At the most basic level, all pain is neuropathic. The term ‘neuropathic pain’ is used to describe irritation, misfire, or dysfunction of nerves caused by intrinsic nerve damage. Pathognomonic symptoms of neuropathic pain are electric sensations like burning and tingling. Leprosy can cause intrinsic damage to nerves,” said Michael Schneck, MD, professor of neurology at Loyola University Medical Center.
Studies have found that neuropathic pain is present in up to 56% of leprosy patients with chronic pain.5
Studies reviewed described neuropathic pain as tingling, burning, electric, stabbing, squeezing, pressure, and cutting. The most common distribution was “glove and stocking.” (This is not surprising because leprosy attacks cooler areas of the body.)2
Another characteristic of leprosy pain is that it may be stimulated by treatment and persist even after leprosy has been cured. 2,4
“Treatment may stimulate an immune system response that may accelerate nerve inflammation and damage,” said Cook.
Flare-ups of pain during and after treatment of leprosy are called lepra reactions. They may occur in up to 50% of patients. Pregnancy may also trigger a lepra reaction.
Treatment of Neuropathic Pain in Leprosy
“Treatment is the same as other neuropathic pain. We don’t try to treat numbness. We do try to control pain. Mainstays of treatment are antidepressants and anticonvulsants. Physical therapy may also help. All neuropathic pain treatment involves a certain amount of trial and error,” said Schneck.
Lepra reaction pain may respond to treatment with prednisone or thalidomide.1
“As with any neuropathic pain, the first rule is to stay away from narcotics. They don’t work for neuropathic pain and may make things worse,” said Schneck.
Filling in the Gaps of Leprosy Pain
There are lots of gaps in our knowledge of pain in leprosy. No clinical trials have been conducted to see which treatments work best for neuropathic pain in leprosy. Unanswered questions include: When does inflammatory neuropathy become neuropathic? When should treatment be started? Can prophylactic treatment prevent neuropathic pain? 2,4 These questions are important because leprosy is just a minor skin disease if there is no nerve involvement. 1
What we may learn from studies of pain in leprosy may be important for more common neuropathic syndromes. The questions about leprosy also apply to postherpetic neuralgia of shingles.
Studies of mixed pain in leprosy may be applicable to mixed pain syndromes, such as multiple sclerosis, Parkinson’s disease, and radiculopathy. 4
Until clinicians have more answers, primary care givers should keep leprosy in mind.
“Think about leprosy when you have a patient with unexplained skin lesions and unexplained pain,” said Cook.
“The other message for caregivers is to help get rid of the stigma attached to the disease. I prefer to call it Hansen’s disease. Leprosy still carries that old biblical stigma. Time for that to end,” said Schneck.
Medically reviewed by: Pat F. Bass III, MD, MS, MPH
1. Health Resources and Services Administration, National Hansen’s Disease (Leprosy) Program.
2. Thakur S, et al. Pain. 2015; 998-1002.