What is Eosinophilia?
Eosinophils are a type of white blood cell that contain specific proteins in their cytoplasm. These cells are created in the bone marrow, the soft, sponge-like tissue in the center of most bones. The production of eosinophils is stimulated by three substances: IL-5, IL-3, and GM-CSF. Once produced, eosinophils stay in the bloodstream for roughly 4.5 to 8 hours before moving to tissues in the body, particularly in the lungs and the digestive tract, where they can stay for 8 to 12 days.
Normally, less than 5% of all white blood cells circulating in your body are eosinophils. When the amount is more than 500 cells in one cubic millimeter of blood, it’s called eosinophilia.
The severity of eosinophilia is classified based on the number of eosinophils in the blood: mild (500 to 1500 cells/mm3 of blood), moderate (1500 to 5000 cells/mm3), and severe (more than 5000 cells/mm3). Hypereosinophilic syndrome, a severe type of eosinophilia, is defined as having more than 1500 cells/mm3 on two separate occasions at least a month apart, or a significant presence of these cells in body tissues.
What Causes Eosinophilia?
Eosinophilia is a condition where you have too many eosinophils, which are a type of white blood cell. This can be due to primary causes, which means the condition arises from something happening in the body itself, or secondary causes, which means it is the result of a different health issue.
Primary causes include:
* Chronic eosinophilic leukemia: a rare type of blood and bone marrow cancer.
* Myeloid and lymphoid neoplasms with rearrangements of PDGFRA, PDGFRAB, or FGFR1 genes: these are specific types of blood cancers where certain genes are out of place.
* Hereditary eosinophilia: eosinophilia that is passed down in families.
* Idiopathic hypereosinophilic syndrome: a blood disorder that leads to too many eosinophils, but doctors don’t know exactly why it happens.
Then, there are secondary causes that make eosinophilia happen:
* Parasitic infestations: This includes when you get infections from certain insects or worms like hookworm, roundworm, cysticercosis, echinococcosis (which can give you a type of cyst), schistosomiasis, strongyloidiasis, trichinellosis, and visceral larva migrans (also known as toxocariasis).
* Fungal and bacterial infections: These include bronchopulmonary aspergillosis, occasional chronic tuberculosis, coccidioidomycosis, disseminated histoplasmosis, and scarlet fever.
* Allergic disorders: Things like bronchial asthma, hay fever, Stevens-Johnson syndrome, drug and food allergic reactions, and DRESS syndrome.
* Skin diseases: Conditions like atopic dermatitis, eczema, pemphigus, Mycosis fungoides, Sezary syndrome.
* Graft versus host reaction: This often happens after an organ transplant when the body rejects the new organ.
* Connective tissue disease: Chrug-Strauss syndrome and eosinophilic myalgia syndrome are examples here.
* Other conditions: reactive pulmonary eosinophilia, tropical eosinophilia, pancreatitis, eosinophilic gastroenteritis are also mentioned.
Risk Factors and Frequency for Eosinophilia
Eosinophilia is a condition that can affect anyone, regardless of gender. Its incidence is influenced by geographical location and other factors. For example, in tropical countries, it’s more common due to parasitic infestations. In contrast, allergic disorders, which are also a common cause, are more often seen in developed countries.
- Eosinophilia is a condition that can affect anyone, regardless of gender.
- Its occurrence can vary based on geographical location.
- Parasitic infestations, which are common in tropical countries, can lead to eosinophilia.
- Allergic disorders also cause eosinophilia and are more prevalent in developed countries.
- The condition is often diagnosed in individuals aged 20 to 50, but can affect individuals of any age.
Signs and Symptoms of Eosinophilia
This disease can show its symptoms in different ways and can range from mild to severe, potentially damaging important body organs. To diagnose it, doctors need to collect a thorough medical history and perform a detailed physical exam. The disease often affects the skin, respiratory system, and digestive tract. Common symptoms such as mild fever, night sweats, tiredness, and weight loss can also be seen in other conditions like immune system disorders and certain syndromes.
- General symptoms include mild fever, night sweats, tiredness, and weight loss
- Skin symptoms involve rashes and itchiness
- Respiratory symptoms include shortness of breath, cough, and wheezing
- For accurate diagnosis, detailed travel history, work environment, drug history, and information about close contacts with HIV, syphilis are required
During a physical examination, the doctor will check your skin and listen to your lungs for certain sounds. They will also examine your abdomen to check for an enlarged spleen.
Testing for Eosinophilia
Before diagnosing the cause of high levels of eosinophils (a type of white blood cell) in your blood, your doctor will first check to make sure it isn’t caused by other conditions. Once secondary causes are ruled out, they check for a specific type of gene fusion in your blood called FIP1L1-PDGFRA. To do this, they’ll start with a diagnostic test called a peripheral smear.
Additional tests can be done on your blood to look for signs of diseases on the cellular level. These tests, called cytogenetic testing and FISH analysis, can provide in-depth information about your cells.
In some cases, the doctor may find other abnormalities in your blood cells that could help them diagnose your condition. If this happens, you might need a bone marrow biopsy. This test allows your doctor to take a small sample of your bone marrow to check for problems. They may also need to analyze your chromosomes using a karyotype and genetic screen.
They may also want to check your B12 and tryptase levels. These, along with the results of the cytogenetic/immunophenotypic testing and marrow findings, can help them diagnose conditions like chronic mastocytosis, types of leukemia, myelodysplastic syndrome, and overlapping blood disorders.
If you have a rash, your doctor may do a skin biopsy to diagnose skin disorders like pemphigoid, eczema, mycosis fungoides, and Sezary syndrome. Other tests, like a chest image, can help them diagnose respiratory conditions like aspergillosis, Loeffler syndrome, and Churg Strauss syndrome. An ultrasound of your abdomen can check for an enlarged spleen. Stool testing can help find parasitic infections.
Treatment Options for Eosinophilia
The treatment for eosinophilia, which is high levels of eosinophils in the body, differs based on the underlying cause. The main goal of the treatment is to reduce organ damage that eosinophilia might cause.
In mild cases where there are no symptoms or signs of any organ damage, doctors typically pursue a wait-and-see approach. However, in emergencies where there’s organ damage or failure, steroids can be given intravenously for quick relief.
For some situations like allergies to certain foods or drugs, or infections, treatment might be easy and straightforward. It could involve simply avoiding the food or drug that’s causing the issue, or treating the infection with antibiotics. However, for other conditions, a team of specialized doctors, including hematologists (who study blood), pulmonologists (who specialize in lung health), and infectious disease specialists might be needed.
In some stubborn cases, such as hypereosinophilic syndrome and chronic eosinophilic leukemia that resist traditional treatment, other medications such as hydroxyurea and interferon-alpha can be effective.
For serious cases, cancer-fighting drugs and stem cell transplants have been found to be beneficial. There are also ongoing medical investigations into the use of special kinds of antibodies for treatment. These antibodies include mepolizumab, which targets a protein (IL-5) involved in the growth of eosinophils, benralizumab that targets the receptor for IL-5, and alemtuzumab that targets a protein found on the surface of immune cells.
Timely medical intervention is crucial to reduce the health impact and risk of death from eosinophilia.
What else can Eosinophilia be?
When doctors are trying to identify an illness, they often narrow down their options based on the symptoms that are most prominent. These symptoms often correlate with a specific body system. For example:
- If the patient has lung-related symptoms, conditions like asthma or bronchopulmonary aspergillosis might be considered.
- If the patient has symptoms that look like hay fever, it could suggest an allergic reaction.
- If the skin is primarily affected, conditions like Mycosis fungoides, Sezary syndrome, eczema, or bullous pemphigoid could be the cause.
What to expect with Eosinophilia
The outlook for someone with eosinophilia can range from a mild illness to a life-threatening situation. This depends on many factors. These factors include the cause of the high eosinophil levels (a specific type of blood cell usually involved in responding to allergies and inflammation), whether any damage to organs has occurred, the specific type of eosinophilia, and how quickly treatment begins.
Possible Complications When Diagnosed with Eosinophilia
Eosinophils, a type of white blood cell, can produce inflammation-causing substances and also contain enzymes which can harm the protective wall of our body’s cells. If not managed properly, this can lead to tissue damage. Depending on the specific cause of this issue, the results can be life-threatening and cause serious damage to vital organs.
Potential Outcomes:
- Tissue damage
- Fatal incidents
- Severe damage to vital organs
Preventing Eosinophilia
If you start to experience a number of symptoms that you can’t explain, or if a pre-existing health condition gets worse for no apparent reason, it’s crucial to seek medical help without delay. During your visit, be sure to give your doctor as much information as you can. This includes information about where you live, any recent trips you’ve taken, and any medications you’re currently taking. This information can help your doctor figure out what might be causing your symptoms.