How Th2 Dominance Impacts Allergies and Immune Health

If you’re struggling with chronic immune system issues such as persistent allergies, frequent infections, or skin conditions, your immune response might be dominated by a dominant “Th2 response.” In this post, I’ll explain what “Th2 dominance” is, how it affects your health, and how to address it through functional medicine.

T cell polarization refers to how your naive CD4 (blank slate) T cells mature into specialized effector T cells that carry out different immune functions. The four main types of effector T cells are shown on this chart:

Ideally, your naive T cells can mature into any of these types as needed. Problems arise when your immune system gets stuck in one mode, such as Th2, which is common in people with allergies and chronic infections.

Many patients come to me with conditions that are driven by an overactive Th2 immune response, making it difficult to fully resolve their symptoms without addressing this underlying issue. Understanding and treating Th2 dominance is crucial for lasting improvement in chronic allergies, infections, and inflammation in certain body areas called “hollow cavities.” This includes the nasal and sinus cavities, the lungs, vagina, bladder and G.I. tract.

Th2 Dominance and Chronic Inflammation: Breaking the Cycle

Th2 cells produce inflammatory cytokines, such as interleukin-4 (IL4), in response to infections or inflammation in body areas exposed to the external environment. The problem arises when these infections or inflammations persist, leading to excessive IL4 production. This signals naive T cells to create more Th2 cells, resulting in Th2 dominance—a vicious cycle of ongoing inflammation. As a result, your body remains inflamed in these areas, increasing susceptibility to infections and chronic conditions.

The bottom line: To heal from these conditions, it’s essential to address Th2 dominance and get IL4 production under control.

Signs You Might Be Stuck in Th2 Dominance

If you experience chronic infections or inflammation in your lungs, sinuses, gut, bladder, or vagina, you may be stuck in Th2 dominance. Some common symptoms include:

• Lungs: Asthma, frequent respiratory infections, bronchitis
• Nose/Sinuses: Allergies, congestion, frequent colds
• Gut: Food intolerances, small intestinal bacterial overgrowth (SIBO), leaky gut
• Bladder: Frequent infections, interstitial cystitis
• Vagina: Recurrent yeast or bacterial infections, vulvodynia

Factors That Drive Th2 Dominance

Various triggers can push your immune system toward a Th2 response, including:

• Mold toxins
• Viral infections (herpes, shingles, Epstein-Barr virus)
• Chronic infections (like Lyme disease)
• Stress
• Environmental toxins
• Allergies and histamine overload
• Aging and cancer

The Link Between Th2 Dominance, Chronic Infections and Autoimmune Disease

When your immune system is stuck in Th2 dominance, it inhibits the production of Th1 cells, essential for fighting bacteria, viruses, and other pathogens. This can result in:

• Frequent colds, flu, and slow recovery from infections
• Chronic viral infections like shingles or Epstein-Barr
• Recurring gut issues like SIBO or candida
• Persistent vaginal or bladder infections

Inhibiting the production of Th1 cells can also result in uncontrolled autoimmune inflammation.

How to Shift Out of Th2 Dominance

In our functional medicine practice, we take this approach to helping people move out of Th2 dominance:

• Managing stress
• Cleaning up diet and gut health
• Clearing environmental toxins
• Reducing pathogen loads (such as chronic infections)
• Taking natural supplements to down-regulate the Th2 response

By addressing these factors and supporting a balanced immune response, you can regain control of your health and break free from the chronic inflammation driven by Th2 dominance.

Take Action Today

If you suspect you’re stuck in Th2 dominance or have chronic immune issues, I can help. Contact me directly to explore personalized strategies for healing and restoring balance in your immune system.