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"How do antihistamines help with allergies?"

ZocdocAnswersHow do antihistamines help with allergies?


My allergies are always bad but this year they are really getting to me. Should I take an antihistamine? What do they do and how do they help with my allergies?


An allergy is a reaction produced from a trigger (for example: pollen) that causes release of histamines by mast cells in your body. When mast cells are triggered, they release histamines (organic compound produced by your body) which bind specific histamine receptors on various tissues throughout the body, including the blood vessels. The inding of histamine to its receptor causes increased vascular permeability which allows fluids to leak through tissues more readily. This translates into allergic symptoms such as runny nose and watery eyes. Antihistamines are a class of medications that compete with histamines in your body for histamine receptor. By binding the histamine receptor, they prevent actual histamines from binding these receptors, which means the histamines can't exert their effect and cause fluid leakage. What all of this translates to, is decreased symptoms of allergies, such as runny nose, watery eyes and postnasal drip. If you have any of these symptoms, it is certainly worth trying an anti-histamine medication to try to alleviate yout symptoms. There are many common over-the-counter medications that are available at a local pharmacy -- the most common one being Diphenhydramine (Brand name: Benadryl). There are many other types of allergy medications if antihistamines are not helpful. Speak to your primary care doctor about all of the options for your allergies.

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