Blood Test: Immunoglobulin E (IgE) - what does a high immunoglobulin e level mean

Allergic diseases are amongst the most prevalent diseases worldwide.
Food, skin, and respiratory allergies are the most common atopic disorders in children. For the past few decades, the prevalence of allergy has increased significantly in Western countries.
Currently, testing for immunoglobulin E (I G E) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions.
Five immunoglobulin isotopes exist, and immunoglobulin E plays major role in allergy and allergic diseases like: Asthma, atopic dermatitis and allergic rhinitis. I G E also contributes significantly to the body's immune response to parasitic infections, which are more prevalent in third-world countries.
A fraction of I G E antibodies is found in the plasma.
If I G E Level is high in the blood we can suspect on several important diseases:
Allergic rhinitis Involvement of the upper airway can cause many patients to suffer from mild seasonal allergies or allergic rhinitis.
Due to repeated inhalation exposure to pollen and other outdoor antI G Ens, type one hypersensitivity occurs, and mast cell degranulation causes epiphora, rhinorrhea, cough, and other symptoms.
Asthma,
Additionally, the involvement of the lower airway in patients with atopic asthma experience immune response to aeroallergens resulting in airway smooth muscle constriction, increased mucus production, and inflammation that manifests as obstructive lung disease.
Atopic dermatitis.
also known as eczema, is an inflammatory skin disorder, which presents with dry and pruritic lesions on the flexure surfaces of extremities as well as head and neck areas.


There are several hypotheses why allergicv diseases increased last several decades.
This hypothesis commonly are controversial and not definitive. For example. According to one hypothesis lack of antioxidants can cause allergic diseases, according to another, excess of antioxidants can cause allergic diseases.
Other hypothesis include hygiene theory, which means the more hygienic environment is the higher chance that the kid will have allergic diseases.
Another hypothesis: intaking of vitamin d in childhood can cause allergic diseases.
Anaphylaxis is a potentially fatal systemic hypersensitivity reaction. Anaphylaxis carried out by an immunologic mechanism is referred to as allergic anaphylaxis. In allergic anaphylaxis, Fc epsilon RI binds I G E and activates mast cells and basophils.
Food allergy.
Food allergy is most commonly triggered by the I G E-mediated hypersensitivity reaction and presents with local or systemic symptoms that begin minutes or hours after the ingestion of the offending food. The proposed pathogenesis involves I G E production against normal food constituents, such as glycoproteins. I G E binds Fc epsilon RI and triggers the downstream signaling cascade, which leads to the production of increased levels of inflammatory mediators. These mediators, in turn, cause an inflammatory response and lead to symptoms involving the skin, gastrointestinal and respiratory tracts, eyes, and the heart, ranging from a mild to severe fatal anaphylactic response.

1) The total I G E assay which is nonspecific and provides only gross information.
The amount of total I G E was considered in the early studies as the simplest way to identify allergic subjects, but it became evident soon that total I G E levels could not be considered a reliable marker of allergy status.
I G E levels significantly higher than the normal threshold, are usually associated with atopic disorders, but also with other conditions.
On the contrary, low or normal values do not exclude the presence of I G E-mediated diseases. As a consequence, total levels of I G E should be carefully interpreted and not considered as an indication for the presence of allergic diseases.
Serum I G E concentration is largely age-dependent. Very low levels it increases with age up to teen ages. After this it starts slowly decreasing. Total serum I G E then declines from the 2nd through the 8th decades of life.
Very high I G E levels are observed in parasitic infestations.
Rarely in multiple myeloma patients producing I G E, and in some primary immunodeficiencies (e.g., Immune dysregulation polyendocrinopathy enteropathy X-linked syndrome (IPEX), Omenn syndrome, Wiskott-Aldrich syndrome, Comel-Netherton syndrome, hyper-I G E syndrome and atypical complete Di George syndrome).
Allergic broncho-pulmonary aspergillosis is the only clinical condition described to date, where the presence of high levels of I G E is strictly related to disease severity.
Increased serum I G E levels can be seen also in a proportion of smokers.
By Department of Pathology, Calicut Medical College - Calicut Medical College, CC BY-SA 4.0, https://commons.wikimedia.org/w/index...
By BruceBlaus - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index...