What Every Woman Should Know About Histamine Intolerance and MCAS

A Root-Cause Q&A with Dr. Krista Imre

At Naturopathic by Design™, we believe that education is a powerful part of healing—especially when it helps you connect the dots between seemingly disconnected symptoms and the deeper root causes.

To unpack one of the most misunderstood but increasingly common issues we see in practice—histamine-related symptoms—I sat down with my colleague and fellow naturopathic doctor, Dr. Krista Imre. Her personal experience with chronic hives and her clinical work with complex patients brings a depth of wisdom to this conversation.

Below is a distilled, root-cause-informed Q&A between the two of us.

Q: What led you to explore histamine in your work?

Dr. Imre:  It began with my own experience. As a teen, I struggled with chronic hives that were difficult to manage. Over time, I realized how many people — especially women under chronic stress — experience similar symptoms without clear answers. This led me to dive deeper into histamine-related conditions.

Q: What are some common causes of Histamine Intolerance?

Dr. Imre:

• Long-term use of histamine-blocking medications (e.g., antihistamines, NSAIDs) can affect DAO enzyme activity.
• Estrogen dominance or fluctuations, as seen in perimenopause or with exogenous hormones, may upregulate histamine and downregulate DAO.
• Thyroid imbalances (hypo- or hyperthyroid) may contribute indirectly.
• Nutrient deficiencies, especially in vitamin C, B6, copper, and zinc, can impair histamine clearance.
• Gut dysbiosis, SIBO, SIFO, and leaky gut reduce DAO production (DAO is produced by intestinal mucosa).
• Chronic stress dysregulates the gut-brain-immune axis, worsening histamine sensitivity.

Q: How is MCAS different from Histamine Intolerance?

Dr. Imre:

Histamine Intolerance is primarily a clearance issue — your body can’t degrade histamine effectively. MCAS is an overproduction issue — your mast cells release histamine (and other mediators such as prostaglandins, tryptase) inappropriately, even in response to benign stimuli like heat, exercise, or mild stress.

While both conditions can cause similar symptoms (rashes, headaches, GI issues), MCAS is more rooted in immune system dysregulation, whereas Histamine Intolerance is more metabolic and gut-based.

Q: What additional symptoms might suggest MCAS?

Dr. Imre:

In addition to histamine-related symptoms (flushing, hives, bloating), MCAS may present with:

• Dizziness, low blood pressure, or rapid heart rate (due to vasodilation)

• Air hunger or shortness of breath (non-asthmatic)

• Tingling or numbness

• Severe chemical or scent sensitivity

  These symptoms tend to flare episodically, often triggered by environmental exposures, infections, or stress.

Q: How do you approach treatment for both conditions?

Dr. Imre: There’s a lot of overlap in the foundations:

• A short-term low-histamine diet can provide symptomatic relief while we investigate root causes.
• We address gut health through microbiome restoration and intestinal repair, since DAO is produced in the gut lining.
• We may support supplementation with DAO if it is clearly deficient.
• We correct nutrient depletions (vitamin C, B6, copper, magnesium — tailored to tolerance).

For MCAS, we often need:

• Mast cell stabilizers like quercetin, luteolin, or chromolyn sodium (when appropriate)
• Nervous system retraining (vagal tone work, breathwork, trauma-informed therapy)
• Targeted use of antihistamines (H1 and H2 blockers) during flares
• Environmental detox (mold, EMFs, chemical irritants) if relevant

Q: Can hormone therapy affect histamine responses?

Dr. Imre:  Definitely. Estrogen stimulates mast cells and can reduce DAO activity. High or unbalanced estrogen — either endogenous or from hormone therapy — can worsen histamine-related symptoms like migraines, anxiety, and hives. Progesterone, on the other hand, can help stabilize mast cells and buffer against estrogen’s stimulating effects.

If symptoms flare on hormone therapy, it doesn’t mean you can’t take it — it means your body may need extra support, or the dose may need adjusting. Sometimes starting with progesterone alone before adding estrogen is more stabilizing.

Q: Are these conditions lifelong?

Dr. Imre:  Not necessarily. These conditions are often adaptive responses to deeper imbalances — gut infections, mold, nutrient depletion, trauma, chronic illness. When we address the root causes, many patients regain tolerance and no longer need restrictive diets or constant interventions.

That said, awareness of triggers and resilience-building strategies (especially for the nervous system and immune system) remains important for long-term well-being.

Final Thoughts

If you’ve felt like your symptoms are “all over the place,” or you’ve been told it’s just anxiety or stress, you’re not alone. These histamine-related conditions can mimic so many others, and they often go unrecognized in conventional care.

At Naturopathic by Design™, we walk with you through the complexity. We see the bigger picture. And we’re here to help you understand your symptoms, rebuild your resilience, and feel safe in your body again.

If you’re ready to explore the next steps, we invite you to book a free 15-minute discovery call or join our email list to receive our tips, guides, recipes, and more, on how to optimize your health through a naturopathic lens.