An Overview of High Histamine (also called Histadelia)

The condition of having excess histamine in the body is called Histadelia. This is apparently relatively common in people on the spectrum and their families. There are a lot of health issues associated with having too much histamine in the body and bloodstream (aside from the obvious issue of allergies), including asthma, migraines and other headaches, anxiety, fearfulness, phobias, panic attacks, bipolar disorder, OCD and tics, cardiovascular symptoms including fluttering heartbeat, dizziness and vertigo, Meneire's Disease, increased sensitivity to pain, abdominal cramping, diarrhea and Irritable Bowel Syndrome, and rosacea. The biochemistry of histamine is the biochemistry of alcoholism and substance abuse as well as other impulsive or compulsive behaviors (possibly including eating disorders). My older son looks intensely ADHD when he is “histamine-y”.

Prolonged exposure to elevated levels of histamine in the body is associated with damage to nerve cells and the central nervous system. It is known to be a cause in MS and suspected to play a role in other neurological disorders including Parkinson's Disease and Chronic Fatigue Immune Deficiency Syndrome. One role of histamine in the body is to regulate the "volume" of sensory input and processing so it is one cause of Sensory Processing Disorder. It also causes the blood brain barrier to become permeable, which could be one reason why high histamine people seem to be more susceptible to injury from toxins in the environment (such as mercury). I've also noticed, while researching the viral issue that we have, that people with viruses in the brain tend to have intense high histamine symptoms and I wonder if high histamine levels is what predisposes some people to have neurological complications from viruses that are relatively benign for most people (by allowing those viruses into the brain).

There seem to be a number of reasons why a person may have high histamine levels. Some bad bacteria in the gut produce histamine and good bacteria neutralize it, so an imbalance of gut flora could be a major factor. The process of methylation is one significant way that the body clears excess histamine out of the bloodstream, so people who under-methylate (or whose methylation systems are clogged with environmental toxins and yeast metabolites) seem to have histamine “back up” in the system. Adrenaline is another major tool the body has for lowering histamine levels (that’s what an epi-pen is) and adrenal fatigue also seems to be a factor. There are several enzymes that help people regulate histamine levels so a deficiency of these enzymes is suspected to be one cause (the two I know of are amylase and diamine oxidase).

Mercury has been shown to damage mast cells and make them more unstable and likely to release histamine. Mercury is also known to cause what’s called Th2 shifting, which is a state of the immune system that leads to auto-immune conditions and chronic inflammation (histamine). People with yeast overgrowth tend to have high histamine symptoms and I’ve heard the theory that some people may be allergic to the yeast in their own body. Ongoing exposure to allergens seems to be another likely possibility. High levels of histamine is a trait that seems to strongly run in families, which has led some researchers to conclude that it must be caused by a genetic variation that causes under-methylation, however gut flora is also passed along in families, as are epigenetic changes.

There are a number of things that can be done to lower histamine levels. There is a supplement regimen, which consists mostly of vitamin C and calcium (calcium pulls histamine out of the tissues and into the bloodstream, and vitamin C helps flush it out of the blood and into the urine). There are also supplements that support methylation that can help, such as SAM-e, methyl-B12, and TMG or DMG. Magnesium can help by stabilizing mast cells. Adrenal support is often helpful. You can try to minimize exposure to allergens. Some people get relief with anti-histamine medication, but responding atypically to medications is a common trait of high histamine people, so this option doesn’t help a lot of people. Histamine is actually a component of many foods so you can minimize dietary exposure (the low histamine diet). The low histamine diet won’t heal gut flora imbalance though, so other diet changes may be needed to address this, as well as probiotics. There are also several enzyme supplements on the market including Histame and Allerase.