Allergy or not an allergy?

Here's an interesting article that clarifies the difference between food allergies and food intolerance:

Part of the confusion is over what is a food allergy and what is a food intolerance, Dr. [Matthew J.] Fenton said. Allergies involve the immune system, while intolerances generally do not. For example, a headache from sulfites in wine is not a food allergy. It is an intolerance. The same is true for lactose intolerance, caused by the lack of an enzyme needed to digest sugar in milk.

And other medical conditions can make people think they have food allergies, Dr. Fenton said. For example, people sometimes interpret acid reflux symptoms after eating a particular food as an allergy.