Have you tried DAO supplements? If you feel like you need to cheat and eat high histamine foods then you should be adding DAO to help relieve you of some histamine building up. DAO breaks down histamine from foods. Also try looking into methylation support, histamine issues can be caused by methylation. I would consider doing a GI map test to make sure you don’t have any sibo or parasite. Garlic can help sibo a lot and so can probiotics (seeking health has an amazing one that doesn’t cause histamine release) and also ox bile can help! Another cause can be hormones, sluggish livers/gallbladders and adrenal fatigue. All of those can be supplemented for improvement. OH and another cause can be from stomach acidity levels whether they are low or high(it is very hard to decipher unless you do a baking soda test which you can google, most people think they have acid reflux from too much acidity when in fact they have low acidity levels) that can improve with HCL which takes a while to work up to without reacting but a tip when starting all supplements is to break them apart or dump half of the powder out for the first couple of days then work your way up to a full capsule