I have done several posts on histamine issues over the last few years — some people close to me have these challenges. Past posts are below:
My Ongoing Dilemna
My problem (i.e. too well trained in scientific method) is the lack of evidence for successful treatment. There are individual stories of success — but such always occur by happenstance for every condition (Cancer, diabetes, etc). One of the most recent pubmed summaries says it well:
“Increased concentration of histamine in blood can occur in healthy individuals after ingestion of foods with high contents of histamine, leading to histamine intoxication. In individuals with histamine intolerance (HIT) ingestion of food with normal contents of histamine causes histamine-mediated symptoms. HIT is a pathological process, in which the enzymatic activity of histamine-degrading enzymes is decreased or inhibited and they are insufficient to inactivate histamine from food and to prevent its passage to blood-stream. Diagnosis of HIT is difficult.” 
- “Histamine-induced food intolerance is not IgE-mediated. Skin-prick testing and specific IgE to food allergens are typically negative….The suspected reason is a diminished histamine degradation based on a deficiency of diamine oxidase.” 
- “RESULTS: Reduced diaminoxidase serum levels leading to occurrence of HIT symptoms like chronic headache, dysmenorrhea, flushing, gastrointestinal symptoms, and intolerance of histamine-rich food and alcohol were significantly more common in patients with AE than in controls. ” 
- “HIT apparently develops as a result of an impaired diamine oxidase (DAO) activity due to gastrointestinal disease or through DAO inhibition, as well as through a genetic predisposition which was proven in a number of patients. The intake of histamine-rich foods as well as alcohol or drugs which cause either the release of histamine or the blocking of DAO can lead to various disorders in many organs (gastrointestinal system, skin, lungs, cardiovascular system and brain), depending on the expression of histamine receptors. Dermatologic sequels can be rashes, itch, urticaria, angioedema, dermatitis, eczema and even acne, rosacea, psoriasis, and other” 
Reduce Histamine or Increase DAO?
My natural inclination is to work to increase DAO. DAO is the body’s natural substance and thus that restoration is important. Reducing histamine intake runs the risk of triggering a feed-back loop: because there is less histamine coming in, DAO production may go into atrophy because of less need — forcing histamine intake to be continuously reduced (usually by excluding most foods and having an incomplete diet.
DAO is fortunately available as a supplement, in fact, I took some this morning because my face swelled up (angioedema) which seems to happen once or twice a year to me once I passed 64. [The underlying mechanism typically involves histamine or bradykinin. ].
- “We found that 10 out of 14 patients had serum DAO activity<10 U/mL, which was the threshold suggested as a cutoff for probable histamine intolerance. Moreover, 13 out of 14 patients subjectively reported a benefit in at least one of the disturbances related to food intolerances following diamine oxidase supplementation. The mean value (±SD) of diamine oxidase activity in the cohort of patients with histamine intolerance symptoms was 7.04±6.90 U/mL compared to 39.50±18.16 U/mL in 34 healthy controls (P=0.0031).” 
The problem is DAO supplements are relatively expensive: $2.00 or more per serving. There is still the risk of a feed-back loop, but at least the diet will be more complete.
The problem may be in your DNA, if you have done a DNA test, you may wish to check
- ” The minor allele at rs2052129, rs2268999, rs10156191 and rs1049742 increased the risk for a reduced DAO activity whereas showing a moderate protective effect at rs2071514, rs1049748 and rs2071517 in the genotypic” 
- “All in all, 51 individuals (11.6%) were identified with a serum DAO level < 3 U/mL, 138 patients (31.4%) had a serum DAO level between 3 and 10 U/mL, and 250 (57.0%) individuals showed DAO serum levels ≥ 10 U/mL… in patients with so far unexplained gastrointestinal (GI) symptoms.” 
- That is 42% are in the range seen with histamine intolerance.
- Role of amine oxidase expression to maintain putrescine homeostasis in Rhodococcus opacus.
- The Rhodococcus family is seen in some microbiome tests, but rarely. It is seen in the new Prescript Assist formula.
- [Effect of antimicrobial substances on diamine oxidase activity of bacteria] 1958.
- Produced by Mycobacterium , again a rarely seen bacteria
- Pyocyanine appears to inhibit DAO (unfortunately, it is unclear what produces this)
Looking data on histamine issues and microbiome at http://microbiomeprescription.azurewebsites.net/Data/SymptomEndProductExplorer?site=gut&filter=133 we see:
- Low 2-Butanone
- Low 2-Methyl-butanal
- Low Cadaverine
- High Vitamin B12
- Low Hydrogen cyanide
- Low Methyl thiocycanide
- High Vitamin B5
- Low Vitamin K
Smaller sample size for http://microbiomeprescription.azurewebsites.net/Metabolite/Explorer?filter=133
- LOW D-Arginine and D-ornithine metabolism
- LOW alpha-Linolenic acid metabolism
At the class level — shifts everywhere, especially with Gammaproteobacteria (13/15 were low or had none)
- At the genus, all had some Lactobacillus, but everyone was low. Same also for Lactonifactor, Anaerotruncus, Candidatus Soleaferrea,
This is an update of my ongoing posts on histamine. Due to the recent contribution of microbiome samples with symptoms, we can see some shifts that may be responsible for low DOA production. Once I get 30 samples with symptoms, I will see about generating diet suggestions based on the major shifts seen.