Symptoms & Diagnosis

HLH can be challenging to diagnose because the initial symptoms may mimic common infections.

What are the symptoms of HLH?

  • Persistent fevers
  • Rash
  • Enlarged lymph nodes
  • Yellowish-looking skin and eyes (jaundice)
  • Coughing, trouble breathing
  • Seizures
  • Altered mental status

Other issues that your child’s doctor may find include:

  • Hepatitis (swelling and inflammation of the liver)
  • Liver failure
  • Low blood counts
  • Enlarged liver
  • Enlarged spleen

How is HLH Diagnosed?

HLH can only be diagnosed with the proper blood tests. Blood tests may include looking at blood cell counts, liver function numbers, and markers of immune system activation such as ferritin and soluble IL-2 receptor levels. A sample of bone marrow may be obtained to look for hemophagocytosis. Doctors may collect some fluid from the spinal canal to look for HLH affecting the brain.

X-rays, CT scans, ultrasounds or MRIs may be performed. Your doctor may also perform testing to look for infections that can be associated with HLH.

There are also specialized blood tests that can be done to rapidly screen patients for the genetic causes of HLH. Detailed genetic testing should also be performed.