Decongestants are often used by those experiencing allergic rhinitis to help relieve sinus congestion and pressure. Pseudoephrine and phenylephrine are common forms of decongestants which are sometimes paired with an antihistamine to both relieve allergic reactions and provide relief from symptoms.  Some common decongestants combined with antihistamines are Allegra-D, Clarinex-D, and Claratin-D, although there are many more available on the market.

Another helpful medication now being used for congestion is in the form of a leukotriene blocker.  If you know someone with asthma, you are probably familiar with Singulair, a montelukast medication used to help open airways.  This has recently been approved for treatment of allergic rhinitis, working well to reduce congestion and sinus pressure.

Simply put, histamines are released by the mast cells to fight off an allergen.  The histamine promotes inflammation in several ways, causing allergic and asthmatic symptoms.  Antihistamines are common medications used to fight the effects of the histamines.  They are considered safe enough to be sold over the counter, with stronger versions prescribed by physicians.  The antihistamine blocks the path of the histamine, thereby reducing your allergy symptoms. 

Many new antihistamine medications are designed to be non-drowsy.  But remember, everyone is different, and what may cause no side effects in one individual might cause noticeable effects in others.  Antihistamines do not relieve stuffy noses, so they are sometimes paired with a decongestant. 

Antihistamines are usually taken daily by mouth in the form of a pill, capsule or liquid.  It is best to begin taking an antihistamine before the allergy season begins.  This will give it time to bind to the H1 receptors for histamine before the actual histamine arrives.