Can Seasonal Allergies Cause Stomach Upset?
- Dr. Brian Lum
- Jul 16
- 5 min read
A stereotypical image of seasonal allergies is a person with a runny nose, congestion, and a sinus headache. But for many, their symptoms do not fit neatly into a diagnosis.
For some people, seasonal allergies only cause symptoms when they are under stress. Others have allergy symptoms after an accident, pregnancy, surgery or the development of an autoimmune disease.
Unconventional Allergy Symptoms
Potential Symptoms Of Seasonal Allergies
Anxiety
Panic Attacks
Depression
Brain Fog
Fatigue
Toe Fungus
Recurrent Pink Eye
Skin Rashes
Digestive Problems
Seasonal Allergies & Digestive Symptoms
Among some of the lesser-known symptoms of seasonal allergies are stomach upset, constipation, diarrhea, GERD, acid reflux, nausea, and stomach cramping.
These digestive symptoms can come with little or no upper respiratory symptoms which is why it can be difficult for these symptoms to be traced back to their source.
The Cause: Histamine
Histamine is released when a perceived threat or foreign substance is detected entering the body.
These foreign substances can be things like dust, pollen, and foods we eat every day.
When a foreign substance is detected, mast cells release histamine to rally your body's healing forces.
In response to histamine release, surrounding blood vessels dilate, increasing white blood cells and blood plasma proteins in that area.
Immune system proteins (antibodies) bind with the invading foreign substance (antigens).
Allergies that cause severe symptoms are a consequence of your immune system overreacting.
This overreaction could be due to many factors but in the case of seasonal allergies, it is usually because the body can't keep up with the number of perceived threats flooding your system.
Histamine Can Cause Stomach Upset
When histamine is released in the gastrointestinal tract, it can cause symptoms like stomach pain, bloating, nausea, diarrhea, and constipation.
Underlying conditions and imbalances can also cause too much histamine to be released.
A few examples are small intestinal bacterial overgrowth (SIBO), underlying or low-grade infection, poor diet, heavy metal toxicity, nutrient deficiencies, and food sensitivities.
What is referred to as histamine intolerance or histamine sensitivity is usually a combination of a few underlying factors (like infection, toxicity, and liver congestion).
In a case of histamine intolerance, an individual can become sensitized to histamine-containing foods, histamine-releasing foods, as well as classic environmental allergens.
A common treatment for histamine intolerance is to be on a special diet and take supplemental medication - but those with histamine intolerance will only have moderate success without personalized treatment to address the underlying cause.
Read more about Histamine Intolerance
Histamine & Liver Congestion
Often, excess histamine and underlying infection combine to make allergy symptoms (like stomach upset) particularly severe.
Ideally, your liver would remove any excess histamine caused by seasonal allergies but when it is congested from the strain of an underlying infection, it gets 'behind' at clearing away this excess histamine.
This is why you may have had mild allergies before but now the symptoms are unbearable.
There is a certain threshold, a certain amount of toxin or infection that your body can comfortably handle but once it passes that point your body falls behind and your symptoms drastically change.
This could mean that your symptoms get more severe, you have them more often, you have different triggers or they are a different set of symptoms entirely.
Functional Medicine Testing
When patients have unusual or severe allergy symptoms I generally run a few allergy-specific tests so we can better tailor treatment.
These tests go beyond the complete blood count (CBC) test you may get at your family doctor or a patch test you may get at your allergist's office - functional medicine testing assesses function at a deep level, so we can get to the root of symptoms.
Histamine Testing
This test uses either blood or urine to give us a baseline to measure immune reactivity. This test will also give us evidence that histamine is the real cause of digestive symptoms.
Mycotoxin Testing (Mold Test)
This test looks at 31 different mold toxins in the urine. Mold toxicity is the most common cause of severe histamine overload or intolerance. Even if you don't see or smell mold in your home or workplace it is worth testing for.
Comprehensive Stool Analysis
This test evaluates specific levels of your protective bacteria, identifies possible hidden gut infections, and assesses your ability to digest food. This is an excellent evaluation for anyway who wants to pinpoint the cause and get rid of their symptoms quickly.
Finding The Cause
Both in cases of histamine intolerance and in seasonal allergies - histamine is not really the 'problem.'
The presence of histamine in your body is normal and vital to your health.
The overproduction of histamine is a result of your body trying to protect you. Finding the cause of this overreaction will be the key to lessening symptoms.
Even if your allergies consist of 'normal' symptoms like a runny nose, sinus headaches, and congestion - if they are affecting your quality of life or you are dependent on anti-histamines to get through your day then an underlying condition is probably making your allergies worse.
Addressing an underlying viral, bacterial or fungal infection can not only help improve allergy symptoms but will make you feel better overall.
It is possible to get lasting, natural relief from seasonal allergies. A personalized, evidence-based approach can make the difference between a spring indoors by the air purifier and one outside enjoying the new flowers.
Online Consultations Available
For over a decade, I have treated complex and chronic illnesses and patients who are sensitive to conventional treatments. This experience has informed the way I help all my patients but has been especially useful in the large number of histamine-related conditions I now see.
With functional medicine diagnostics and treatment options, scientifically supported mind/body practices, powerful natural supplements and specific and personalized application - histamine symptoms can be drastically reduced or eliminated.
I am currently accepting new patients and offer online consultations worldwide.
If you would like to schedule a free 15 minute consultation with me to ask questions about becoming a patient click the link below.
Histamine Course
In the fall, we will be releasing 'Mastering Histamine Intolerance and Mast Cell Activation Syndrome (MCAS): A Complex Illness Specialist’s Guide.'
Please visit our page to sign up for our mailing list and, if you have time, to fill out our survey to help us make this course the best possible resource for you!
Written by Stephanie Lum and Dr. Brian Lum
Disclaimer: If you think that you may have a medical emergency, call your doctor or 911 immediately. No action or inaction should be taken based solely on the contents of this information. Nor should you ever delay seeking medical advice or treatment due to the information contained on this Website. The information on this Website is not intended to diagnose, treat, cure, or prevent any disease or medical condition. The information discussed is not intended to replace the advice of your healthcare provider. Reliance on the information provided by this Website, Dr. Brian Lum, or Functional Healthcare Institute is solely at your own risk.