Histamine and Allergies

Histamine can dilate blood vessels to bring more blood flow and white blood cells to local areas, which causes rashes, redness, heat, and pain. This process can help the body clear up damaged tissues or can lead to chronic inflammation or allergies if too much histamine is released for too long. An allergy is an abnormal, acquired sensitivity to certain substances including pollen, drugs, and numerous environmental triggers. Type I hypersensitivity is characterized by the excessive activation of mast cells and basophiles by a kind of antibody called IgE, triggering a systemic inflammatory response that can result in symptoms as benign as a runny nose or as life-threatening as anaphylactic shock and death.
It has been shown that cells that produce histamine have the most wakefulness-related firing-patterns of any neurons so far recorded. They fire rapidly during waking hours, fire more slowly during periods of relaxation or tiredness, and completely stop firing during REM and non-REM sleep. Firing of histamine-producing cells is recorded just before an animal shows signs of waking. That is why if a person does not sleep enough, he/she will produce more histamine in the body. Abnormally higher histamine level in the body can lead to chronic allergies and inflammation.
Certain kinds of drink and food can also induce higher levels of histamine such as spoiled fish and red wine. So if you have allergic reactions right now, it is wise to avoid seafood and red wine until your allergy clears up. If you have an acute injury and your body tries to clear up the damaged tissue by releasing more histamine, you may rest more than you usually do. In that way, your body will not produce too much histamine to cause chronic inflammation.
Many histamine releasing cells can be sensitized by estrogen. When women are close to menopause, their progesterone level drops dramatically and their estrogen level fluctuates, creating the condition called estrogen dominance. Estrogen dominance can also be caused by high sugar intake, non-ovulation cycles, too much coffee, obesity, environmental pollution, alcoholism, and post-partum hormone changes. That is why women tend to develop different kinds of allergies and autoimmune diseases during their periods of hormone changes such as puberty, pregnancy, or menopause if the histamine level is too high.