Signs, symptoms and diagnosis of HLH

The symptoms of HLH can be confused with common childhood illnesses but
are more severe. They include a skin rash, raised temperature and swollen liver,
spleen and lymph glands. There may be anaemia, infection or bruising and
bleeding. If the brain is affected, a child may show symptoms such as seizures,
ataxia (wobbliness) or drowsiness.

Diagnosis of HLH

Initially, blood samples are taken for testing in the laboratory. A wide range of
tests will be carried out, including full blood count to look for low numbers of
each type of blood cell. More specialised tests will check liver function and look
for signs and causes of infection. Some of these blood tests have to be sent to a
specialist laboratory and it takes several days for the results to come through.
Other samples, such as bone marrow or lymph node tissue, may give extra clues.
If there are neurological (brain) symptoms, a sample of cerebrospinal fluid may
be taken by lumbar puncture.

If HLH is strongly suspected, genetic tests will be done which can identify the
faulty genes in the primary forms of HLH.