Hopeful, one more thing. Cayenne (and most if not all other hot spices) trigger a histamine response.
I get vulvodynia nerve pain within 30 seconds of ingesting hot spice and the pain and burning lasts for days before resolving. Clearly the food has not even entered the digestive process, so it has to be getting into circulation via a nerve pathway.
Vulvodynia is known to have a mast cell component, possibly too many mast cells and they are being triggered. Anything that triggers mast cells to release histamine is going to cause symptoms for people with histamine issues. It sounds like you already have identified a histamine problem for yourself.
My triggers are all fermented, aged, cultured foods and also hot spices and citrus and yeast and gluten grains (and for some reason oats):
Vinegars
Hot spices, especially hot pepper/cayenne but also cloves, cinnamon, etc
Cultured foods (cheeses, yogurt, sour cream, buttermilk, etc)
Fermented foods (sauerkraut, kimchi, soy sauce, etc)
Cured/processed foods (smoked, cured meats)
Alcohol
Citrus (all kinds)
Chocolate (aged)
Gluten
Oats
Yeast (Saccharomyces strains in particular)
Multiple medications, too many to list
I do not take any meds except an occasional aspirin/advil for an especially irritating headache.