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Understanding primary HLH

Finding out that you or your loved one have primary HLH can be overwhelming. The following information is for you and your family to learn about primary HLH, its signs and symptoms, and what you might expect after diagnosis.

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Primary HLH is a rare genetic condition, which means it can be passed down in families. It usually affects babies and young children, but it can affect older children and adults as well.

Primary HLH is caused by a genetic mutation that keeps the immune system from working properly.

  • When the immune system is working properly, it finds and attacks foreign invaders like viruses and bacteria to protect the body
  • In people with primary HLH, the immune system doesn’t work right. It attacks a person’s own cells and organs instead
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Definition and pronunciation of primary hemophagocytic lymphohistiocytosis (HLH)
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Definition and pronunciation of primary hemophagocytic lymphohistiocytosis (HLH)

What is the difference between primary and secondary HLH?

Researchers are still working to fully understand HLH, but here’s what we know about the disease so far. There are 2 main types of HLH—primary and secondary.

Although the symptoms for both may be similar, it is thought that each has a different cause and may require different approaches to treatment.

  • Although the symptoms for both may be similar, it is thought that each has a different cause and may require different approaches to treatment

Primary HLH could be inherited, which means it is passed down in the genes from a parent to a child.

Primary HLH
could be inherited, which means it is passed down in the genes from a parent to a child.

Secondary HLH could be triggered by other medical problems, such as an infection or a disease like cancer.

Secondary HLH
could be triggered by other medical problems, such as an infection or a disease like cancer.

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To understand more about your or your loved one’s condition, it’s important to know what happens in the body of someone with primary HLH and what some of the symptoms can be.

Please be sure to speak with your doctor about HLH, including signs and symptoms.

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This video can help you learn more about primary HLH and how it's treated.