Hansen’s disease, also known as leprosy, affects about 200 people in the U.S. each year. Despite its fearsome reputation, this bacterial infection is treatable and curable with modern medicine.

Hansen’s disease gets its name from Gerard Hansen, the physician who discovered the bacteria that causes the infection. The older term “leprosy” comes from a Greek word that means “to scale,” as in peeling skin.

“The name ‘Hansen’s disease’ is preferred because of the stigma associated with leprosy,” says dermatologist Jennifer Adams, MD, who received additional training from the National Hansen’s Disease Program and treats patients with the condition.

Early warning signs

Symptoms vary based on how your immune system responds to the infection. Key signs include:

• Light-colored spots on the skin that have no feeling when touched.
• Bumps on the skin accompanied by fever.
• Loss of sensation in hands and feet.
• Numbness in affected areas.

“There are different types of Hansen’s disease based on how your immune system is reacting to the infection,” Dr. Adams says. “Commonly people experience light spots on the skin that don’t have nerve sensation.”

How is it transmitted?

The bacteria that cause Hansen’s disease is thought to spread through respiratory droplets during close, prolonged contact with an infected person.

“It can take one to 20 years after you’re infected to start developing symptoms,” Dr. Adams says. “On average, it’s about 5 to 7 years after the infection when you start developing symptoms.”

In the southeastern U.S., the nine-banded armadillo carries the same strain of Hansen’s disease bacteria found in some patients. However, scientists aren’t entirely sure how transmission occurs between animals and humans.

Treatment and recovery

The good news: Hansen’s disease responds well to antibiotics.

“It’s like any other bacterial infection – thankfully, we have antibiotics,” Dr. Adams says. “There’s an antibiotic regimen that’s a once-monthly dose of pills.”

Treatment typically lasts one to two years, depending on the severity. After just a few doses, patients are no longer contagious.

The importance of early treatment

If left untreated, Hansen’s disease can cause permanent nerve damage, which may cause: 

• Burns from touching hot objects without feeling them.
• Eye problems due to facial nerve damage.
• Wounds and sores in numb areas.
• Difficulty using hands and feet normally.

Breaking down the stigma

Historical fear of Hansen’s disease led to harmful practices that still affect public perception today.

“In the U.S., we had leprosariums, which were locations where people living with leprosy had to go and live the rest of their lives,” Dr. Adams says. 

These facilities, which mostly stopped operating in the 1920s, created lasting fear in communities. People worried that a diagnosis would separate them from their families forever.

Who’s at risk?

Most people don’t need to worry about getting Hansen’s disease. About 95% of the global population is naturally immune to the bacteria.

“It’s really hard to catch Hansen’s disease,” Dr. Adams says. “You have to be the person in that 5% of the population that is susceptible to it and living in close contact with an infected person for prolonged period of time.”

The majority of Hansen’s disease cases occur in:

• India.
• Brazil.
• Indonesia.

“In the U.S., about 200 cases yearly are diagnosed, but globally, it’s closer to 200,000 to 250,000 people diagnosed annually,” Dr. Adams says.

In countries where Hansen’s disease is rare, diagnosis can be delayed.

“In non-endemic countries like the U.S., a lot of times on average, patients are misdiagnosed for five to eight years before they get the correct diagnosis,” Dr. Adams says. “It’s something that is not on people’s radar.”

A curable condition

Hansen’s disease is not the permanent, disfiguring condition many people imagine. With proper treatment, patients can expect full recovery, though some nerve damage may be permanent if treatment is delayed.

“It’s not a permanent infection. It’s a bacterial infection, just like you could get any other skin infection and treat it with antibiotics,” Dr. Adams says. “It’s very curable.”