Illuminated Hypereosinophilic syndrome

By Dr Nicola Davies

Hypereosinophilic syndrome (HES) refers to a group of rare blood disorders that are characterized by a marked overproduction of eosinophils (white blood cells that lay an important role in immunity). While the exact prevalence of HES is unknown, the World Health Organization reported age-adjusted incidence of about 3-4 people per 10,000,000 between 2001 and 2005.

Patients diagnosed with HES usually have a peripheral eosinophil count greater than 1500/µl and evidence of multiorgan damage due to eosinophilic infiltration.2 Symptoms of HES vary widely depending on the area of eosinophil infiltration, and may include skin rash, abdominal pain, muscle weakness and debilitating fatigue.