Hypereosinophilic syndrome

Overview

Hypereosinophilic syndrome is organ damage or dysfunction caused by an excess of disease-fighting white blood cells called eosinophils.

Hypereosinophilic syndrome (hy-per-ee-o-SIN-o-phil-ik) is rare. It can affect any tissues in the body. Common targets include the skin, lungs, digestive tract, heart and nervous system.

If a condition is found to cause hypereosinophilic syndrome, then treating the underlying condition also may lower eosinophil levels. Other treatments include medicines that reduce the number of eosinophils in the bloodstream.

Causes

Eosinophils are important in fighting parasites and bacteria. They also regulate other immune system cells and proteins that cause allergic reactions.

HES occurs when high levels of these white blood cells last a long time. The cells themselves or their byproducts can move into organs, where they can cause damage or dysfunction.

Terms to know

You may hear the following terms regarding HES.

• Eosinophilia is a higher than typical number of eosinophils circulating in the bloodstream.
• Hypereosinophilia is a high number of eosinophils that lasts for an extended period, usually at least one month.
• Hypereosinophilia syndrome is organ damage or destruction caused by long-term high eosinophils.

Types of hypereosinophilia

Persistent increases in these white blood cells may be caused by a number of factors. General categories of hypereosinophilia based on cause include the following:

• Primary hypereosinophilia is caused by cancers of the bone marrow or blood that directly increase the production of eosinophils.
• Secondary hypereosinophilia, also called reactive hypereosinophilia, is caused by conditions that typically activate white blood cells, such as:
• Parasitic or bacterial infections.
• Allergies.
• Immune system disorders.
• Long-lasting inflammatory diseases.
• Drug reactions.
• Familial hypereosinophilia is an inherited disorder.
• Idiopathic hypereosinophilia has no cause that can be found. Most cases are idiopathic.

Diagnosis

A diagnosis of is HES is based on persistent high levels of eosinophils and evidence of organ damage. Diagnostic tests are used to determine what has caused an increase of eosinophils and whether any tissues have been affected.

Your healthcare professional will ask a number of questions about symptoms, family medical history, medicines and possible exposure to disease.

Tests to determine cause

Your healthcare professional orders tests to determine the cause of increased eosinophils. These may include:

• Blood tests to detect autoimmune conditions, infections, or evidence of blood-related cancers.
• Allergy tests to detect environmental or food allergies.
• Stool tests to detect parasitic infections such as hookworm.
• Genetic test to check for rare gene mutations that can cause HES.
• Bone marrow samples to detect possible cancers or other diseases of the bone marrow.

Tests to assess organ damage

Other tests are used to find out whether organs have been affected by high eosinophils. These may include:

• Blood tests to check liver and kidney function.
• Imaging tests to study the appearance and function of organs.
• Echocardiogram to check heart function.
• Lung function tests to measure how well you breathe in and out.
• Tissue samples of organs that check for the presence of eosinophils or evidence of tissue damage.

Preparing for an appointment

You'll likely begin with an appointment with your primary healthcare professional. Depending on the results of early tests and symptoms, you may need an appointment with specialists in multiple fields. The healthcare team may include a specialist in the following fields:

• Allergies, called an allergist.
• Blood disorders, called a hematologist.

Consider taking a relative or friend along to your appointments to help remember all the information provided.

Here's some information to help you get ready for an appointment, and what to expect from your healthcare professionals.

What you can do

Before your appointment, make a list of:

• Signs and symptoms, including any that seem unrelated to the reason for the appointment.
• Any medications, including vitamins, herbs and over-the-counter medicines; the dosages for each; and reasons for taking them.
• Key personal information, including any major stresses or recent changes in your life.

If HES is considered or you have a diagnosis of HES, you might ask these questions:

• Will I need additional tests?
• What are the treatment options?
• What are the benefits and risks of each treatment?
• Should I see additional specialists?
• What tests or appointments are the highest priority?
• Are there brochures or other printed material that I can have? What websites do you recommend?

What to expect from your doctor

The healthcare professional is likely to ask you several questions. Be ready to answer them to allow time later to cover other points you want to address. Examples include:

• When did you first begin experiencing symptoms?
• Are the symptoms continuous or occasional?
• How severe are the symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen the symptoms?
• Do you have any allergies or skin conditions?
• Have you been exposed to any parasites such as hookworm?
• Have you traveled out of the country lately?
• Have you recently started a new medicine?
• Does anyone in your family have a history of HES?