From the Guidelines
Low immunoglobulin E (IgE) total levels generally do not indicate a medical concern and are often considered normal. IgE is an antibody that plays a key role in allergic responses and fighting parasitic infections. Low IgE levels may simply reflect a lack of allergic conditions or recent parasitic infections. In some rare cases, very low or undetectable IgE can be associated with certain immunodeficiency disorders like hyper-IgM syndrome or severe combined immunodeficiency (SCID), but this is uncommon and would typically present with other symptoms and abnormal immune markers 1. No specific treatment is needed for isolated low IgE levels in the absence of other symptoms or immune abnormalities. The clinical significance of low IgE should be interpreted in the context of a person's overall health status, other laboratory findings, and any presenting symptoms. Some patients with low IgE levels may have other immunoglobulin deficiencies, such as selective IgA deficiency (SIGAD), which can increase the risk of infections and autoimmune diseases 1. However, the management of these conditions is focused on treating the underlying immunodeficiency and preventing complications, rather than specifically addressing the low IgE levels. If you have concerns about your immune function, it's best to discuss these results with your healthcare provider who can provide personalized guidance based on your complete medical picture. Key points to consider include:
- Low IgE levels are often normal and do not require treatment
- Rarely, low IgE can be associated with immunodeficiency disorders
- The clinical significance of low IgE should be interpreted in the context of overall health status and other laboratory findings
- Management of underlying immunodeficiency is the primary focus, rather than specifically addressing low IgE levels.
From the Research
Definition of Low Immunoglobulin E (IgE) Levels
- Low IgE levels are defined as values below 2.5 IU/mL 2 or <2 kU/L 3
- An undetectable serum IgE (<2 IU/ml) occurs in only 3.3% of the general population 4
Clinical Implications of Low IgE Levels
- Low IgE levels may indicate an underlying systemic disease or primary immunodeficiency (PID) 2
- Patients with low IgE levels are at risk of recurrent infections, autoimmune/inflammatory diseases, and malignancies 2, 3
- Low IgE levels can be a marker for hypogammaglobulinaemia or common variable immunodeficiency (CVID) 3, 4
Association with Other Immunoglobulin Levels
- Low IgE levels are associated with low IgG3 and IgG4 in allergy referrals, while immunodeficiency referrals with low IgE have significantly lower IgG1, IgG2, and IgG4 levels 5
- The IgG1/IgG4 ratio is increased in subjects with low IgE, regardless of whether they are controls or have CVID 4