Eosinophilia
Encyclopedia
Eosinophilia is a condition in which the eosinophil count in the peripheral blood exceeds 0.45×109/L (450/μl). A marked increase in non-blood tissue eosinophil count noticed upon histopathologic examination is diagnostic for tissue eosinophilia. Several causes are known, with the most common being some form of allergic reaction or parasitosis. Diagnosis of eosinophilia is via a complete blood count
, but diagnostic procedures directed at the underlying cause vary depending on the suspected condition(s). An absolute eosinophil count is not generally needed if CBC shows marked eosinophilia. The location of the causal factor can be used to classify eosinophilia into two general types: extrinsic, in which the factor lies outside of the eosinophil cell lineage; and intrinsic eosinophilia, which denotes etiologies within the eosiniphil cell line. Specific treatments are dictated by the causative condition, though in idiopathic eosinophilia, the disease may be controlled with corticosteroids. With the exception of the idiopathic form, eosinophilia is a sign of a disorder, and not a disorder in and of itself.
(primary) or, more commonly, secondary to another disease. In the United States, allergic or atopic diseases are the most common causes, especially those of the respiratory
or integumentary
systems. In the developing world, parasites
are the most common cause. A parasitic infection of nearly any bodily tissue
can cause eosinophilia.
Diseases that feature eosinophilia as a sign include the following:
and leukemia
produce less marked eosinophilia. Of solid tumor neoplasms
, ovarian cancer
is most likely to provoke eosinophilia, though any other cancer can cause the condition. Solid epithelial cell tumors have been shown to cause both tissue and blood eosinophilia, with some reports indicating that this may be mediated by interleukin
production by tumor cells, especially IL-5 and/or IL-3. This has also been shown to occur Hodgkin lymphoma, in the form of IL-5 secreted by Reed-Sternberg cells. In primary cutaneous T-cell lymphoma, blood and dermal eosinophilia are often seen. Lymphoma cells have also been shown to produce IL-5 in these disorders. Other types of lymphoid malignancies have been associated with eosinophilia, as in lymphoblastic leukemia with a translocation between chromosomes 5 and 14. It has been indicated that a gene encoding an eosinophil hematopoietin is overexpressed in patients displaying eosinophilia. A translocation between chromosomes 5 and 14 n patients with acute B lymphocytic leukemia resulted in the juxtaposition of the IL-3 gene and the immunoglobulin heavy-chain gene, causing overproduction production of IL-3, leading to blood and tissue eosinophilia.
, to severe life threatening drug reactions with eosinophilia and systemic symptoms
(DRESS). Drugs that have been shown to cause DRESS are aromatic anticonvulsants and other antiepileptics, sulfonamides, allopurinol
, nonsteroidal anti-inflammatory drugs (NSAIDs), and certain antibiotics. The reaction which has been shown to be T-cell mediated may also cause eosinophilia-myalgia syndrome
.
, complement complex (C5-C6-C7), interleukin 5
, and histamine (though this has a narrow range of concentration).
(CBC). However, in some cases, a more accurate absolute eosinophil count may be needed. Medical history is taken, with emphasis on travel, allergies and drug use. Specific test for causative conditions are performed, often including chest x-ray
, urinalysis
, liver and kidney
function tests, and serologic tests for parasitic and connective tissue diseases. The stool is often examined for traces of parasites (i.e. eggs, larvae, etc.) though a negative test does not rule out parasitic infection; for example, trichinosis
requires a muscle biopsy
. Elevated serum B12 or low white blood cell alkaline phosphatase
, or leukocytic abnormalities in a peripheral smear indicates a disorder of myleoproliferation. In cases of idiopathic eosinophilia, the patient is followed for complications. A brief trial of corticosteroids can be diagnostic for allergic causes, as the eosinophilia should resolve with suppression of the immune over response. Neoplastic disorders are diagnosed through the usual methods, such as bone marrow aspiration and biopsy for the leukemias, MRI/CT to look for solid tumors, and tests for serum LDH and other tumor markers.
may be used. However, immune suppression, the mechanism of action of corticosteroids, can be fatal in patients with parisitosis.
Complete blood count
A complete blood count , also known as full blood count or full blood exam or blood panel, is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood...
, but diagnostic procedures directed at the underlying cause vary depending on the suspected condition(s). An absolute eosinophil count is not generally needed if CBC shows marked eosinophilia. The location of the causal factor can be used to classify eosinophilia into two general types: extrinsic, in which the factor lies outside of the eosinophil cell lineage; and intrinsic eosinophilia, which denotes etiologies within the eosiniphil cell line. Specific treatments are dictated by the causative condition, though in idiopathic eosinophilia, the disease may be controlled with corticosteroids. With the exception of the idiopathic form, eosinophilia is a sign of a disorder, and not a disorder in and of itself.
Causes
Eosinophilia can be idiopathicIdiopathic
Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
(primary) or, more commonly, secondary to another disease. In the United States, allergic or atopic diseases are the most common causes, especially those of the respiratory
Respiratory system
The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...
or integumentary
Integumentary system
The integumentary system is the organ system that protects the body from damage, comprising the skin and its appendages...
systems. In the developing world, parasites
Parasitic disease
A parasitic disease is an infectious disease caused or transmitted by a parasite. Many parasites do not cause diseases. Parasitic diseases can affect practically all living organisms, including plants and mammals...
are the most common cause. A parasitic infection of nearly any bodily tissue
Tissue (biology)
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
can cause eosinophilia.
Diseases that feature eosinophilia as a sign include the following:
- AllergicAllergyAn Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
disorders- AsthmaAsthmaAsthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
- Hay feverHay FeverHay Fever is a comic play written by Noël Coward in 1924 and first produced in 1925 with Marie Tempest as the first Judith Bliss. Laura Hope Crews played the role in New York...
- Drug allergies
- Allergic skin diseaseDermatitis-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...
s- PemphigusPemphigusPemphigus is a rare group of blistering autoimmune diseases that affect the skin and mucous membranes.In pemphigus, autoantibodies form against desmoglein. Desmoglein forms the "glue" that attaches adjacent epidermal cells via attachment points called desmosomes...
- Dermatitis herpetiformisDermatitis herpetiformisDermatitis herpetiformis , or Duhring's disease,Freedberg, et al. . Fitzpatrick's Dermatology in General Medicine. . McGraw-Hill. ISBN 0-07-138076-0. is a chronic blistering skin condition, characterised by blisters filled with a watery fluid...
- Pemphigus
- Asthma
- Parasitic infections
- Some forms of malignancy
- Hodgkin's lymphomaHodgkin's lymphomaHodgkin's lymphoma, previously known as Hodgkin's disease, is a type of lymphoma, which is a cancer originating from white blood cells called lymphocytes...
- Some forms of Non-Hodgkin lymphomaNon-Hodgkin lymphomaThe non-Hodgkin lymphomas are a diverse group of blood cancers that include any kind of lymphoma except Hodgkin's lymphomas. Types of NHL vary significantly in their severity, from indolent to very aggressive....
- Hodgkin's lymphoma
- Systemic autoimmune diseases (e.g. SLESystemic lupus erythematosusSystemic lupus erythematosus , often abbreviated to SLE or lupus, is a systemic autoimmune disease that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage...
) - Some forms of vasculitisVasculitisVasculitis refers to a heterogeneous group of disorders that are characterized by inflammatory destruction of blood vessels. Both arteries and veins are affected. Lymphangitis is sometimes considered a type of vasculitis...
(e.g. Churg-Strauss syndromeChurg-Strauss syndromeChurg–Strauss syndrome is a medium and small vessel autoimmune vasculitis, leading to necrosis. It involves mainly the blood vessels of the lungs , gastrointestinal system, and peripheral nerves, but also affects the heart, skin and kidneys. It is a rare disease that is non-inheritable and...
) - Cholesterol embolismCholesterol embolismCholesterol embolism occurs when cholesterol is released, usually from an atherosclerotic plaque, and travels along with the bloodsteam to other places in the body, where it obstructs blood vessels...
(transiently) - CoccidioidomycosisCoccidioidomycosisCoccidioidomycosis is a fungal disease caused by Coccidioides immitis or C. posadasii. It is endemic in certain parts of Arizona, California, Nevada, New Mexico, Texas, Utah and northwestern Mexico.C...
(Valley Fever), a fungal disease prominent in the US Southwest. - Interstitial nephropathy
Neoplastic eosinophilia
Hodgkin lymphoma (Hodgkin’s disease) often elicits severe eosinophilia, however, non-Hodgkin lymphomaNon-Hodgkin lymphoma
The non-Hodgkin lymphomas are a diverse group of blood cancers that include any kind of lymphoma except Hodgkin's lymphomas. Types of NHL vary significantly in their severity, from indolent to very aggressive....
and leukemia
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...
produce less marked eosinophilia. Of solid tumor neoplasms
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, ovarian cancer
Ovarian cancer
Ovarian cancer is a cancerous growth arising from the ovary. Symptoms are frequently very subtle early on and may include: bloating, pelvic pain, difficulty eating and frequent urination, and are easily confused with other illnesses....
is most likely to provoke eosinophilia, though any other cancer can cause the condition. Solid epithelial cell tumors have been shown to cause both tissue and blood eosinophilia, with some reports indicating that this may be mediated by interleukin
Interleukin
Interleukins are a group of cytokines that were first seen to be expressed by white blood cells . The term interleukin derives from "as a means of communication", and "deriving from the fact that many of these proteins are produced by leukocytes and act on leukocytes"...
production by tumor cells, especially IL-5 and/or IL-3. This has also been shown to occur Hodgkin lymphoma, in the form of IL-5 secreted by Reed-Sternberg cells. In primary cutaneous T-cell lymphoma, blood and dermal eosinophilia are often seen. Lymphoma cells have also been shown to produce IL-5 in these disorders. Other types of lymphoid malignancies have been associated with eosinophilia, as in lymphoblastic leukemia with a translocation between chromosomes 5 and 14. It has been indicated that a gene encoding an eosinophil hematopoietin is overexpressed in patients displaying eosinophilia. A translocation between chromosomes 5 and 14 n patients with acute B lymphocytic leukemia resulted in the juxtaposition of the IL-3 gene and the immunoglobulin heavy-chain gene, causing overproduction production of IL-3, leading to blood and tissue eosinophilia.
Drug reactions
Drug hypersensitivity reactions (allergies) are a common cause of eosinophilia, with manifestations ranging from diffuse maculopapular rashMaculopapular rash
A maculopapular rash is a type of rash characterized by a flat, red area on the skin that is covered with small confluent bumps. The term "maculopapular" is a compound: macules are small, flat discolored spots on the surface of the skin; and papules are small, raised bumps...
, to severe life threatening drug reactions with eosinophilia and systemic symptoms
DRESS syndrome
DRESS syndrome stands for Drug Reaction with Eosinophilia and Systemic Symptoms. The term was coined in a 1996 report in an attempt to simplify terminology for a syndrome recognized as early as 1959...
(DRESS). Drugs that have been shown to cause DRESS are aromatic anticonvulsants and other antiepileptics, sulfonamides, allopurinol
Allopurinol
Allopurinol is a drug used primarily to treat hyperuricemia and its complications, including chronic gout.- Mechanism of action :...
, nonsteroidal anti-inflammatory drugs (NSAIDs), and certain antibiotics. The reaction which has been shown to be T-cell mediated may also cause eosinophilia-myalgia syndrome
Eosinophilia-myalgia syndrome
Eosinophilia–myalgia syndrome is an incurable and sometimes fatal flu-like neurological condition that is believed to have been caused by ingestion of poorly produced L-tryptophan supplements...
.
Pathophysiology
IgE mediated eosinophil production is induced by compounds released by basophils and mast cells, including eosinophil chemotactic factor of anaphylaxis, leukotriene B4Leukotriene B4
Leukotriene B4 is a leukotriene involved in inflammation. It is produced from leukocytes in response to inflammatory mediators and is able to induce the adhesion and activation of leukocytes on the endothelium, allowing them to bind to and cross it into the tissue...
, complement complex (C5-C6-C7), interleukin 5
Interleukin 5
Interleukin 5 or IL-5 is an interleukin produced by T helper-2 cells and mast cells. Its functions are to stimulate B cell growth and increase immunoglobulin secretion. It is also a key mediator in eosinophil activation. IL-5 is a 115-amino acid -long TH2 cytokine that is part of the...
, and histamine (though this has a narrow range of concentration).
Diagnosis
Diagnosis is by complete blood countComplete blood count
A complete blood count , also known as full blood count or full blood exam or blood panel, is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood...
(CBC). However, in some cases, a more accurate absolute eosinophil count may be needed. Medical history is taken, with emphasis on travel, allergies and drug use. Specific test for causative conditions are performed, often including chest x-ray
Chest X-ray
In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...
, urinalysis
Urinalysis
A urinalysis , also known as Routine and Microscopy , is an array of tests performed on urine, and one of the most common methods of medical diagnosis...
, liver and kidney
Renal function
Renal function, in nephrology, is an indication of the state of the kidney and its role in renal physiology. Glomerular filtration rate describes the flow rate of filtered fluid through the kidney...
function tests, and serologic tests for parasitic and connective tissue diseases. The stool is often examined for traces of parasites (i.e. eggs, larvae, etc.) though a negative test does not rule out parasitic infection; for example, trichinosis
Trichinosis
Trichinosis, also called trichinellosis, or trichiniasis, is a parasitic disease caused by eating raw or undercooked pork or wild game infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm. There are eight Trichinella species; five are...
requires a muscle biopsy
Muscle biopsy
In medicine, a muscle biopsy is a procedure in which a piece of muscle tissue is removed from an organism and examined microscopically. A biopsy needle is usually inserted into a muscle, wherein a small amount of tissue remains. Alternatively, an "open biopsy" can be performed by obtaining the...
. Elevated serum B12 or low white blood cell alkaline phosphatase
Alkaline phosphatase
Alkaline phosphatase is a hydrolase enzyme responsible for removing phosphate groups from many types of molecules, including nucleotides, proteins, and alkaloids. The process of removing the phosphate group is called dephosphorylation...
, or leukocytic abnormalities in a peripheral smear indicates a disorder of myleoproliferation. In cases of idiopathic eosinophilia, the patient is followed for complications. A brief trial of corticosteroids can be diagnostic for allergic causes, as the eosinophilia should resolve with suppression of the immune over response. Neoplastic disorders are diagnosed through the usual methods, such as bone marrow aspiration and biopsy for the leukemias, MRI/CT to look for solid tumors, and tests for serum LDH and other tumor markers.
Treatment
Treatment is directed toward the underlying cause. However, in primary eosinophilia, or if the eosinophil count must be lowered, corticosteroids such as prednisonePrednisone
Prednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...
may be used. However, immune suppression, the mechanism of action of corticosteroids, can be fatal in patients with parisitosis.