With the onset of allergy season in Texas comes dread from people acutely sensitive to the pollens, weeds, grasses, shrubs, and molds that create a cascade of symptoms from mild congestion and sneezing to itchy eyes and fatigue. Seasonal allergies can occur throughout the year, with some experiencing the worst symptoms during “cedar fever” and ragweed season in the fall, or hypersensitivity to pollens and grasses in the spring and summer months.

While pollen counts can be measured and tracked, helping people understand when they might experience allergy symptoms, many people find their bodies struggling to cope year-round. For some, the severity of their allergies during and outside of typical allergy seasons can feel like fighting a never-ending virus. In reality, it’s often the body’s heightened sensitivity to environmental triggers—fueled by excess histamine—causing symptoms that feel like being sick with a cold or flu. For someone with histamine intolerance, allergy symptoms can be debilitating and negatively impact their cognitive function as well as energy level.

Curious why some people experience environmental allergies more severely and persistently than others? The answer lies in how our bodies trigger and metabolize histamine.

What Is Histamine, and Why Does It Matter?

Histamine is a naturally occurring compound in our bodies (and in some foods, including fermented foods, aged cheese, spinach, soy, etc.) that plays several key roles, including immune defense, digestion, expanding blood vessels, and neurotransmission. When the body encounters allergens, histamine is released as part of the immune response, helping the body flush out perceived invaders. However, for people with high histamine levels or histamine intolerance, the body either releases too much histamine or struggles to break it down efficiently. Paired with heightened inflammation, increased stress, and lowered immune function in the body, this imbalance can lead to ongoing symptoms such as:

• Chronic congestion, runny nose, sneezing, and itchy eyes
• Skin rashes and itchy skin
• Headaches and migraines
• Mild earaches and low-grade fever
• Hoarse voice or loss of voice
• Fluctuating energy levels, full-body fatigue, and exhaustion
• Brain fog and other temporary cognitive impairment
• Gastrointestinal issues like bloating, nausea, and irritable bowels
• Mood disturbance like anxiety, irritability, and depression
• Difficulty falling asleep or staying asleep
• Low blood pressure or irregular heartbeat

When histamine builds up faster than it can be cleared, it doesn’t just cause allergy-like symptoms—it can affect mood, hormones, and inflammation throughout the body. The combination of symptoms experienced can vary each season, with some seasons being more intense from one year to the next. To further complicate the presentation of allergy symptoms, some people experience only a couple of symptoms while others may experience an overwhelming mixture of symptoms, causing them to question if their immune system is fighting a contagious illness.

Sound familiar? Let’s talk about the underlying connections to our mental and physical health.

The Link Between Histamine, Hormones, and Chronic Conditions

In a growing body of peer-reviewed research, high histamine and histamine intolerance have been correlated with several chronic and neurobiological conditions, including premenstrual dysphoric disorder (PMDD), endometriosis, polycystic ovarian syndrome (PCOS), and neurodivergence such as attention-deficit hyperactivity disorder (ADHD). Histamine intolerance can be caused by various factors such as genetics, gut issues, diamine oxidase enzyme (DAO) deficiency, chronic inflammation, medications, nutritional deficiencies, hormone imbalances, and alcohol consumption.

Histamine can have a significant impact on hormonal fluctuations, such as during the menstrual cycle. Histamine interacts closely with estrogen and spikes when estrogen levels increase, which is why many women and people menstruating notice allergy symptoms intensify mid-cycle or just before their period. Elevated histamine can trigger cramping, irritable bowels, anxiety, and sleep issues, which are symptoms that overlap with PMDD and endometriosis flare-ups. Similarly, individuals with autoimmune conditions may experience histamine surges as part of systemic inflammation. In those with neurodivergence (like ADHD), research suggests histamine plays a role in dopamine regulation, sleep cycles, and sensory sensitivity. In other words, histamine does not just affect your sinuses—it can influence how your brain and body feel day to day. Irritable bowel syndrome (IBS) and intestinal permeability (leaky gut) are also strongly connected to histamine intolerance due to a person’s digestive issues worsening when the body tries to break down excess histamine. Furthermore, histamine intolerance can negatively impact fibromyalgia due to the inflammation causing increased pain and fatigue.

Supporting the Histamine-Sensitive Body

This information may feel uncomfortably familiar to you and leave you wondering what can be done to reduce the negative influence of histamine on your allergies, chronic health conditions, and mental health. From a holistic perspective, managing histamine intolerance involves supporting both the body’s ability to break down histamine and reducing unnecessary triggers. This may include:

• Supporting gut health, since histamine is mostly produced and cleared in the digestive tract (think about adding a soluble fiber solution to your daily routine along with a high-quality probiotic)
• Identifying and reducing environmental allergens like dust, mold, or pet dander (consider running an air purifier with a HEPA filter when you’re home, especially while sleeping)
• Supporting liver detoxification pathways through hydration, gentle movement, and nutrient support (aim to drink half your body weight in ounces of water each day)
• Eating a low-histamine or histamine-balanced diet focusing on fresh vegetables, fresh meats, and unprocessed foods (include a hearty dose of healthy fats and proteins like olive oil, coconut oil, almonds, chia seeds, and flax)
• Practicing stress regulation, since cortisol and histamine levels often rise together during chronic stress (self-care looks different for everyone—find ways to move your body, breathe, walk through the trees, listen to the birds singing, and intentionally focus on staying present in the moment while being out in nature)

The Takeaway

If you feel like you’re allergic to everything, constantly fighting fatigue, or noticing that your allergies flare alongside hormonal or emotional shifts, histamine could be playing a larger role than you realize. Understanding your body’s relationship with histamine is the first step toward balance. Once you become aware of your body’s sensitivities, specific allergy symptoms that fluctuate through the shifts in seasons, chronic health conditions you live with such as autoimmune or inflammatory diseases that present similar symptoms, and the ways these are all connected, you will hear your body’s inner wisdom guiding you to take practical steps to find relief in the moment. Through intentional self-care, nutritional awareness, and nervous system support, it’s possible to reduce reactivity, calm inflammation, and restore a sense of ease both physically and emotionally.

Curious to learn more about how your experiences with allergies may be connected to histamine intolerance, or how your chronic health conditions might be connected to these issues? I’d love to meet you for a consultation to dive into strategies tailored toward your individual needs.