In addition to reviewing the two excellent articles linked to, be sure and visit the AFP by Topic page. The editors write:
AFP editors have identified our best collection of information on the most commonly sought topics and assembled it here for your convenience. The editors will periodically add to these to ensure that they remain as useful as possible. This is the core of AFP; we hope you find it useful.
The above is organized into three sections: a complete list of topic collections, the most popular topics, and recently updated topics. This resource is outstanding.
Here are links to two practical articles on allergic rhinitis from the American Family Physician: