When you think of histamines, the first thing that comes to mind is probably allergies. But histamines play many other roles in our bodies.
Histamines are responsible for estrogen metabolism, the sleep-wake cycle, neurotransmitter production, and digestion.
Symptoms of Histamine Intolerance
Some common symptoms of a histamine intolerance are:
- Rashes
- Hives
- Breathing problems
- Headaches or migraines
- Food intolerances
- Digestive issues
- Behavior ups and downs
- Emotional issues
Symptoms of histamine intolerance occur when there’s an issue with histamine breakdown and an overflow of histamine from outside sources. You can think of the body’s histamine like a bucket – problems arise if it fills too quickly or drains too slowly.
When our bodies “empty” histamine properly, there are minimal or no symptoms present. When our body’s histamine bucket fills too fast or empties too slow, then the level increases and “overflows.” As a result you experience a histamine intolerance.
Causes of Histamine Intolerance: What Makes Some People’s “Bucket” Overflow?
Histamine intolerance is usually a combination of too much histamine coming into the body combined with slower histamine degradation.
Food such as spinach, strawberries, pineapple, canned fish, and otherwise healthy fermented foods like kombucha or kimchi have high histamine levels. Additionally, leftovers, or any food that’s been sitting for a while is higher in histamine. Eating too much of these foods can cause an overload of histamine, especially if your body is already slow to eliminate histamine.
How Histamine Intolerance Affects Autistic Children
It’s not uncommon for autistic children to have elevated levels of histamine. One reason for this is that autistic individuals often have impaired methylation which is one way the body clears histamine.
Inflammation in general and inflammation in the brain especially, are often issues for autistic children. Histamine can lead to increased levels of inflammation and cause issues with sleep, learning, and behavior.
Studies have shown that blocking histamine in some patients with autism can help reduce some of these bothersome behaviors.
What Slows Down Histamine Degradation – Why is the “Bucket” Emptying Slowly?
There are a few reasons you or your child may be experiencing slowed histamine degradation.
- Genetics: Diamine oxidase (DAO) and histamine N-methyltransferase (HNMT) are two enzymes in our bodies that break down histamines. A small genetic error can result in less of these enzymes.
- A Damaged or Inflamed Gut: DAO and HNMT are produced by the brush borders cells in our gut. These cells are the gut’s first line of defense. If the brush border cells are damaged DAO and HNMT don’t get produced in the correct amounts.
Determining if Your Child Has a Histamine Intolerance
The easiest way to find out if you or your child has a histamine intolerance is with an at home histamine test. You should check with your pediatrician or medical provider if you have any hesitations about administering this test.
Alternatively, you can give your child a dose of an antihistamine like diphenhydramine and watch for behavior improvements. When you’re choosing an antihistamine, remember to use a formula that’s free of food dyes and titanium dioxide. You don’t want to burden your child’s body with other inflammatory ingredients.
As always, follow the dosing instruction on the bottle or contact your medical care provider for guidance.

Finding the Cause of Your Child’s Histamine Intolerance
If your child has an issue with histamine intolerance, going with a low histamine diet alone won’t solve the problem. You need to find and address the root cause.
The OAT test is a great place to start. With one simple urine sample we can learn a lot of information.
Histamine problems rarely stand alone so make sure to investigate other possible issues and root causes such as:
- Food sensitivities
- Gut health
- Genetics
- Methylation issues
Once you get to the root of the problem you’ll be able to help your child live a better, more productive, and less painful life.
Be gentle with yourself. You’re doing a great job.
I hope this information has been helpful to you as part of creating Your Autism Game Plan.Do you have a topic you’d like to learn more about? Email me at joya@yourautismgameplan.com
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