Who knew? Leprosy is still found throughout the world including the U.S. The states most affected are Arkansas, California, Florida, Hawaii, Louisiana, New York, and Texas.
Most cases arise in people who have lived overseas where leprosy is more common. The highest number of cases in the world are in India.
The proper name for leprosy is Hansen’s Disease. The name comes from the scientist in Norway who discovered the bacteria that causes it (Mycobacterium leprae).
Florida currently has the highest rate in the U.S. There were 15 new cases in 2023. The nine-banded armadillo is a natural host, and the new cases were in locations where these animals are more common.
Hansen’s Disease (leprosy) is most often identified by finding a discolored patch or patches of skin that are often numb. This is due to the bacteria damaging nerves to the skin patches.
Infected individuals may also have enlarged nerves visible under the skin. Also, their skin tends to be thick, stiff, and/or dry.
In more advanced cases, they may have painless ulcers on the bottom of their feet. Other signs may include loss of eyebrows or eyelashes or painless swelling or lumps on their face.
It usually takes a long time (years) after being infected before signs of the illness appear.
Diagnosis is made by a biopsy of the involved skin. Treatment is very effective. It requires 2 or 3 different antibiotics given for one or two years.
The CDC also points out that “ancient leprosy,” such as is mentioned in religious texts, is not the same as modern leprosy. For example, the Greek word translated into English as leprosy actually just means any skin disorder or may refer to “mildew on clothes, possessions, or living quarters.”
Once treatment begins, in just a few days the patients are no longer contagious and can safely go to school or jobs. In reality, Hansen’s Disease is not very contagious; it usually requires prolonged exposure to an infected individual before someone else can get it from them.
Also, according to the CDC, “95% of adults are immune” due to a vigorous immune response to the bacteria.
We often imagine Hansen’s Disease as causing fingers, toes, and noses to be missing. This is because the bacteria attacks the nerves to these areas so that cuts and trauma can go unrecognized.
Over time, these untreated wounds lead to destruction and resorption of those structures. It is a very late finding so it is now rare.
Hansen’s Disease is frightening to many people. This is mainly based on stories from past centuries. We now have highly effective treatments.
If you or someone you know may have been exposed, e.g., touched an armadillo, and now have one or more numb, discolored skin patches, it is a good idea for them to see a physician.
Peter M. Hartmann, MD
Family Medicine & Psychiatry
