Immunoglobulin E (IgE) and Allergic Asthma

Asthma can be described as allergic or non-allergic. Allergic (extrinsic) asthma is associated with immunoglobulin E (IgE)—an antibody generated by the immune system, in this case, in response to a normally harmless substance. In contrast, non-allergic (intrinsic) asthma episodes are not typically triggered by exposure to a substance and are not associated with IgE.

Given the role of IgE in certain asthma cases, treatment may involve an anti-IgE medication to lower amounts of this antibody and its effects. A blood test to check your levels can help determine whether this may or may not be useful in your case.

The Role of IgE

IgE is naturally produced by B cell lymphocytes, a type of immune white blood cell. This antibody normally activates physical responses to help your body fight infections.

For some people, exposure to allergens—which are harmless, non-infectious substances (like dust or pollen)—can also trigger the body to produce and release IgE.

In these situations, IgE antibodies bind to the allergen and trigger an inflammatory response that can manifest with allergy symptoms such as a skin rash, sneezing, and swollen lips. When it results in asthma, it is considered the allergic type.

Common allergens include:

• Animal dander
• Cockroaches
• Dust mites
• Molds
• Pollen

When your body releases IgE, a cascade of immune responses follows, some of which are mediated by other immune cells in the body. IgE is believed to bind to and activate several types of immune cells, such as:

• Basophils
• Lymphocytes
• Mast cells

When IgE binds with any of these cells, it can overstimulate your immune system. Additionally, your capillaries widen and become leakier, increasing inflammation by allowing the immune cells to cluster around the allergen.

Symptoms Caused by Excess IgE

When you have allergic asthma, your bronchi (airways) can become narrow and inflamed due to the rush of immune cells—and this rapidly exacerbates your asthma symptoms.

Not only do the inflammatory cells prevent air from passing through your airways, but your airways may also suddenly spasm, making it difficult for air to pass as you try to breathe.

Increased levels of IgE may contribute to symptoms of asthma, such as: 

• Wheezing
• Chest tightness
• Shortness of breath
• Recurrent cough

The symptoms are usually mild, but they can be quite severe and may cause serious consequences, such as a life-threatening respiratory crisis.

Diagnosis

If have not yet been formally diagnosed with asthma, your doctor will review your specific symptoms. Those that suggest an allergic cause of your asthma include itchy eyes, nausea, sneezing, coughing, and congestion.

Sometimes the pattern of symptoms can point to allergic asthma when symptoms tend to occur in relation to allergen exposure. Allergy testing can help identify what may be triggering your condition.

IgE Testing

If there is a concern that you have allergic asthma, your doctor might test your IgE level to help make a diagnosis and to help guide your treatment plan. Your doctor will consider your results in the context of your symptoms and other diagnostic measures.

Your antibody level can vary, and your IgE level might be normal even if you have allergic asthma. A high IgE level can't confirm a diagnosis of asthma. High IgE can only suggest that you may have some sort of allergic disorder.

Immune disorders and infection due to a parasite are also associated with high levels of IgE. For example:

• Churg-Strauss syndrome, a type of vasculitis (inflammation of the blood vessels)
• Allergic bronchopulmonary aspergillosis, a hypersensitivity to a soil fungus known as Aspergillus fumigatus

Children who have asthma are more likely to have elevated IgE levels than adults with asthma. Asthma that begins for the first time during adulthood, called adult-onset asthma, is more likely to be intrinsic, non-allergic asthma.

Treatment

There are a number of treatments for allergic asthma, including avoiding allergens that are asthma triggers, if possible. However, it is not always possible to avoid allergens, especially if they are highly prevalent in the environment.

Inhalers containing immunosuppressants or bronchodilators are commonly used to treat allergic asthma. 

Treatment with anti-IgE is another approach that can be used along with bronchodilators. Your IgE level can help your doctor determine whether you might benefit from treatment that can lower IgE. But a high level is not a requirement for treatment with an anti-IgE.

Your doctor might consider this if your asthma is persistent or if you have side effects from your treatment. Reducing your IgE, if elevated, is a more targeted method of preventing symptoms of allergic asthma than immunosuppression with steroids, which has long been a way of managing asthma by reducing inflammation.

Xolair (omalizumab) is an anti-IgE medication approved by the U.S. Food and Drug Administration (FDA) for the treatment of allergic asthma for adults and children over the age of 6. It binds to IgE antibodies to reduce their effects and help prevent (though not treat) allergic asthma attacks.

Indications for Xolair include:

• Severe or persistent asthma that's inadequately controlled with inhaled corticosteroids and a positive skin test or positive blood allergy test
• Chronic skin rash that's inadequately controlled with antihistamines

Xolair is given every two to four weeks as a subcutaneous (under the skin) injection administered by a healthcare provider. Side effects can include injection site reactions, infections, headaches, and sore throat.

A Word From Verywell

Allergic asthma is caused by an overreaction to one or more specific allergens, and you are likely to experience symptoms every time you are exposed to them. High levels of IgE can support a diagnosis of allergic asthma, and anti-IgE medication may help control your symptoms.

If you are already on an allergic asthma treatment plan without adequate control of your asthma, speak with your doctor about your persistent symptoms. You may benefit from revising your treatment approach.