What are the symptoms of histamine intolerance? It’s a bit of a complicated question. No two cases of histamine intolerance are the same, and because we have histamine receptors all throughout the body, symptoms vary significantly from person to person.
Even for the same person, your symptoms may wax and wane depending on factors such as what you’re eating, the season you’re in, your level of stress, medications you’re taking, or even where you are in your menstrual cycle if applicable.
In this article, I’ll cover a number of common histamine intolerance symptoms, how to identify them, and what they might mean. But first, a bit of background information.
What Causes Histamine Intolerance Symptoms?
Histamine is a natural chemical that is released by white blood cells called mast cells as an important part of a healthy immune system response to a threat or allergen.
However, there are many things that can contribute to an excessive build up of histamine in the body, causing an individual to react with symptoms that are typically inflammatory in nature. These may include:
• Excessive mast cell activation or mast cell instability. While it is normal for mast cells to release histamine in response to a threat, many factors can cause mast cells to activate unnecessarily, leading to the excessive release of histamine and other inflammatory molecules.
• High histamine foods. Many foods and drinks contain some level of histamine, and histamine content always increases as any food ages, spoils, or ferments. Some foods are also thought to trigger the release of histamine, or block the action of the enzyme diamine oxidase (DAO) that breaks histamine down. High histamine (or histamine releasing) foods include citrus fruits, aged cheeses, fermented foods like sauerkraut, alcohol (especially red wine), legumes, mackerel, and aged or cured meats like salami.
• Gut bacteria imbalances. In addition to being released by mast cells and found in certain foods, histamine is produced by certain kinds of gut bacteria. If the gut microbiome is off balance, histamine producing microbes may outnumber histamine degrading (or neutral) ones, increasing levels of histamine throughout the body.
• Low DAO levels or reduced DAO activity. DAO is the enzyme that breaks down dietary histamine within the digestive tract. If your body is releasing insufficient DAO (often due to a genetic predisposition), or its activity is being blocked (can be caused by various factors including nutritional deficiencies), you may have a reduced ability to tolerate even low to moderate levels of histamine-rich foods.
When talking about histamine intolerance, we often use the metaphor of a bucket. We all have our own histamine bucket that fills up and empties based on several different factors, as discussed above. If the bucket gets too full, we may start to experience symptoms.
In this sense, histamine intolerance can in some cases be thought of as more of a (hopefully transient) imbalance than a clear-cut diagnosis or a disease. Any individual can experience histamine intolerance symptoms if their bucket gets too full. But with the right identification, understanding, and treatment, in most cases, these can be managed and the individual returned to health.
Histamine Intolerance Symptoms Throughout the Body
The inflammation brought on by histamine, although critical within the immune system, can result in a wide range of unpleasant and sometimes mysterious symptoms. The most widely recognized example would be a headache and itchy eyes, typical of what you might experience when you have an allergic reaction.
But there are many other possible symptoms. Why is this?
In order for histamine to cause symptoms or reactions in the body, it needs to bind to a kind of protein structure called a receptor.
There are four different types of histamine receptors found all over the body, which helps to explain why so many different systems and areas of the body may be affected, from the digestive tract and the skin to the brain, immune system, and reproductive system.
Symptoms will vary depending on which receptors are being activated and in which tissues. But regardless of the part of the body being affected, inflammation is at the core of most symptoms of histamine intolerance.
While they may vary, some of the most common reactions associated with histamine intolerance include:
• Headaches or migraines
• Runny nose and watery, red, itchy eyes
• Nasal congestion, itchy nose
• Itchy skin
• Flushing of face and/or chest
• Respiratory symptoms including asthma, sinusitis, or shortness of breath
The most visually obvious appear as skin problems:
• Skin rashes, itchiness
• Eczema; dry, patchy, or scaly skin
• Tissue swelling
Common gastrointestinal symptoms that may show up are:
• Chronic constipation
• Loose stools or diarrhea
• Flatulence and bloating
• Stomach cramps
• Leaky gut
• Nausea and/or vomiting
Histamine intolerance and mast cell instability can also affect the nervous system and cardiovascular system, leading to symptoms including:
• Chills and shivers
• Low blood pressure
• High blood pressure
• Arrhythmia (irregular heart rate)
• Sleep disorders or trouble sleeping
• Difficulty regulating body temperature
• Unexplained exhaustion
• Brain fog or trouble focusing
People who have histamine intolerance can experience a diverse range of different symptoms that some may dismiss or misdiagnose. You may also receive other diagnoses such as irritable bowel syndrome (IBS) or chronic fatigue syndrome which, while not wrong, fail to take into consideration an underlying issue related to histamine.
The American Journal of Clinical Nutrition states that 80% of those who suffer from histamine intolerance are women. This may be a result of a bidirectional relationship between estrogen and histamine levels.
Many women who suffer from histamine intolerance report worsening symptoms just before their periods. Other symptoms may include:
• Dysmenorrhoea (severe period pains and cramps)
• Irregular menstrual cycles
How To Know If It’s Histamine Intolerance
Unlike true food allergies and even many food intolerances, histamine intolerance is not easily detected with a blood test or a skin-prick test.
So, with so many possible manifestations and no conclusive tests, you might be wondering how to determine whether or not your symptoms are related to histamine.
When other causes have been ruled out, allergy tests alone can not correctly diagnose all your symptoms, and histamine intolerance is suspected, the best “test” is to start an elimination diet, removing all high histamine foods.
To do this, follow a low-histamine diet consisting of low-histamine foods such as fresh vegetables, and fresh meat, and gluten free grains for 4 weeks. Monitor your symptoms throughout this period. If your symptoms improve, it’s likely that you have some level of histamine intolerance.
From there, you can move on to identifying and correcting underlying imbalances that may be contributing to this intolerance. For example, addressing gut microbiome imbalances (dysbiosis), leaky gut, and SIBO can make a big difference. It’s also worth investigating your hormonal balance and levels of DAO-supporting and mast cell-stabilizing nutrients.
Speak with your Functional Medicine practitioner about supplements that may help, including the DAO enzyme, vitamin C, magnesium, mast cell stabilizers like quercetin, and probiotics.
To learn more and customize your plan, check out my complete histamine intolerance course here. Or, for even more personalized guidance, request a one-on-one consultation with me.
To get started, you may request a personalized functional medicine consultation with Dr. Gannage to discuss whether testing may be right for you.
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