What is Type 2 Inflammation?


When a person has an allergic reaction, the immune system responds by activating immune cells and antibodies. Cells include eosinophils, mast cells and T-cells that release histamine that cause inflammation. In some people with allergic diseases, the immune system produces excess inflammation. This is an overactive immune response called Type 2 inflammation.

What causes Type 2 inflammation?

Research is ongoing, but genetics appears to play a role. The following is an overview of the conditions that can cause Type 2 inflammation in different parts of the body.

Health conditions that may be affected by Type 2 inflammation include:

  • aspirin-exacerbated respiratory disease (AERD)
  • asthma exacerbations
  • chronic rhinosinusitis with nasal polyps (CRSwNP)
  • chronic urticaria (hives)
  • eczema (atopic dermatitis)
  • eosinophilic asthma
  • eosinophilic esophagitis (EoE)
  • sleep apnea

Type 2 inflammation could be the underlying reason causing these conditions. It could also be the reason the condition is hard to control or why someone may have more than one of these conditions.


Healthcare providers can diagnose Type 2 inflammation through testing. These tests measure your levels of white blood cells called eosinophils and blood IgE levels. High levels of eosinophils indicates Type 2 inflammation is present. There are also breathing tests for the lungs called fractional exhaled nitric oxide (FeNO).

Treatment is available for people with Type 2 inflammation and specific to each disease state. Medical researchers have developed specialized medications that can inhibit Type 2 inflammation.

Work with your healthcare provider to decide what treatment is best for you. Consider the severity of your symptoms. Discuss whether your condition is hard to control. Discuss what previous medications or treatments you have tried. Find out if Type 2 inflammation is connected to any other medical conditions you may have.

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Some biologic medications target cells and pathways to block Type 2 inflammation before it can start. Learn more at

Young woman taking an aspirin substitute because she has AERD

Aspirin-exacerbated respiratory disease (AERD) and Type 2 inflammation

AERD, also known as Samter’s Triad, is a chronic inflammatory disease that involves:

  • asthma;
  • recurrent nasal polyps (soft, teardrop-shaped, non-cancerous, painless growths in the sinuses);
  • a sensitivity to aspirin and/or other non-steroidal anti-inflammatory drugs (NSAIDs).

Type 2 inflammation plays a key role in asthma and inflamed airways. It also plays a key role in nasal polyps related to chronic rhinosinusitis. AERD patients with Type 2 inflammation may experience worsened asthma symptoms, sinus congestion and nasal polyps.

If you’re diagnosed with AERD and your symptoms are not getting better, talk with your doctor. Treatments for severe asthma and nasal polyps are available. These may include corticosteroid nasal sprays and biologic medications that treat the source of asthma and nasal polyp symptoms.

AERD symptoms, diagnosis and treatment

AERD Patient Education Video Series

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Asthma and Type 2 inflammation

Type 2 inflammation with asthmas most often associated with moderate to severe asthma. Research shows it affects between 55% to 70% of adults with severe asthma.

Allergic asthma and eosinophilic asthma involve Type 2 inflammation. In allergic asthma, an allergic response activates immune cells that release inflammatory mediators. This triggers inflammation in the airways. It makes it hard to breathe. In eosinophilic asthma, certain proteins (called interleukins) cause high levels of white blood cells called eosinophils. When there are too many eosinophils in the blood, it can cause inflammation in the airways.

If you have hard to control or severe asthma with Type 2 inflammation, you may experience worsened symptoms of cough, wheeze and shortness of breath. It can lead to an increased risk of asthma exacerbations and decreased lung function.

If you continue to have hard-to-control asthma, consider seeing an asthma specialist. You may want to ask about biologics, especially if other medications such as inhaled corticosteroids are not helping. Biologics can target the cells that cause inflammation. They can stop symptoms before they can start.

When Asthma Is More Than Just Asthma: Type 2 Inflammation

Photo of young woman with Nasal Polyps illustration in the background 

Chronic rhinosinusitis with nasal polyps (CRSwNP) and Type 2 inflammation

Chronic rhinosinusitis with nasal polyps (CRSwNP) involves inflamed sinus and nasal cavities. The condition is often caused by Type 2 inflammation. Research shows as many as 85% of CRSwNP cases are associated with Type 2 inflammation. Many people diagnosed with CRSwNP also have asthma or allergic rhinitis.

High levels of eosinophils in the blood can lead to Type 2 inflammation in the sinus and nasal cavities. When there is inflammation in the nose, it can become a breeding ground for nasal polyps. This can lead to worsened CRSwNP symptoms: nasal congestion, postnasal drip and difficulty breathing through the nose. It can also lead to frequent sinus infections.

CRSwNP treatment options include corticosteroid nasal sprays and possibly surgery if nasal polyps are large. Talk with an allergist. If corticosteroid nasal sprays are not helpful, advanced treatments called biologics are available. Biologic medications target eosinophils that cause inflammation.

What is Chronic Rhinosinusitis with Nasal Polyps (CRSwNP)?

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Chronic Urticaria and Type 2 inflammation

Chronic urticaria are hives that occur for 6 weeks or longer. More than 500,000 people live with the condition in the United States. Hives are round, raised, and itchy welts on the skin. They can be painful at times. Type 2 inflammation is often an underlying cause of chronic urticaria. It could be the cause of chronic idiopathic urticaria (also called chronic spontaneous urticaria).

Skin impacted by urticaria has certain proteins (called interleukins) that can cause high levels of eosinophils in the tissue. When there are too many eosinophils in the blood, it can trigger inflamed skin.

Antihistamines are the first line of treatment for chronic urticaria. If they don’t work, then your doctor may consider biologics. These medications block the proteins that increase eosinophils in the blood, stopping the inflammation before it can start. Talk with an allergist or dermatologist to find the right treatment for you

Chronic Urticaria: causes, symptoms, treatment

Baby with severe eczema on its face 

Eczema and Type 2 inflammation

Eczema is a chronic inflammatory skin condition. (Atopic dermatitis is a form of eczema). Type 2 inflammation is a significant contributor to moderate to severe eczema. Skin with eczema has certain proteins (called interleukins) that cause high levels of eosinophils. When there are too many eosinophils in the blood, it can trigger eczema skin rashes.

The proteins also can reduce the production of filaggrin. Low levels of filaggrin allow moisture to escape from the skin and allergens and bacteria to invade. This can lead to dry, scaly and itchy skin.

Medical researchers are developing medications that inhibit Type 2 inflammation. JAK inhibitors are eczema medications that can stop or reduce Type 2 inflammation by limiting certain proteins that cause allergic reactions and inflamed skin. Biologics approved for moderate to severe eczema block the proteins that increase levels of eosinophils, stopping inflammation before it can start. If you have severe eczema, talk with an allergist or dermatologist to find the right treatment for you.

Learn more about eczema

What is Eczema

What is Moderate to Severe Eczema

Middle aged woman sitting on her couch and reaching for her asthma inhaler with one hand while holding her airways with the other hand. 

Eosinophilic asthma and Type 2 inflammation

Eosinophils are a common asthma biomarker for Type 2 inflammation. These are white blood cells that cause airway inflammation. When there are too many eosinophils in the blood, it leads to leading to increased inflammation. This is called eosinophilic asthma.

People with eosinophilic asthma may experience worsened symptoms of cough, wheeze and shortness of breath. Research shows a connection between too many eosinophils in the blood and the future risk and severity of asthma attacks.

If quick-relief and daily controller medications are not helping, talk with your asthma specialist. Biologics can reduce the eosinophils in the blood and the inflammation. They can help open up the airways and control a patient’s breathing. Talk with an asthma specialist if biologics are right for you.

What is eosinophilic asthma?

young man having trouble breathing 

Eosinophilic esophagitis (EoE) and Type 2 inflammation

Eosinophilic esophagitis (EoE) is a chronic condition consisting of high levels of eosinophils in throat tissue. It involves Type 2 inflammation and swelling in the esophagus. This can make it hard to swallow food. Symptoms also may involve reflux, chest pain and food getting stuck in the throat.

EoE is treated by modifying the diet to avoid trigger foods and/or medications. Inhaled or liquid corticosteroids can help control inflammation in the throat. If dietary modifications and corticosteroids do not help, advanced treatments called biologics are available to treat EoE. Biologics block certain proteins to decrease eosinophils, thus reducing inflammation. Talk with your doctor about which treatment option is best for you.

Eosinophilic esophagitis: symptoms, causes, diagnosis and treatment

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Sleep apnea and Type 2 inflammation

Sleep apnea occurs when your muscles relax during sleep, causing soft tissue in the throat to break down and block the upper airway. This can result in a less airflow and oxygen making its way to the lungs.

Researchers are investigating the relationship between sleep apnea and Type 2 inflammation. It is believed the decreased oxygen and re-oxygenation that occurs during sleep apnea may cause an immune response and inflammation. It could lead to an asthma attack in someone diagnosed with asthma.

Sleep apnea treatment does not involve medication. Patients use a continuous positive airway pressure (CPAP) machine to help maintain an open airway during sleep. Lifestyle changes are also recommended.

Sleep apnea: symptoms, causes, diagnosis and treatment

Reviewed by:
Bradley Chipps, MD, FACAAI, is a board-certified allergist and pediatric pulmonologist with Capital Allergy and Respiratory Disease Center in Sacramento, California. He earned his medical degree from University of Texas Medical Branch in Galveston in 1972. He is Past President of the American College of Allergy, Asthma and Immunology (ACAAI).

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