Anaphylaxis: First aid

A life-threatening allergic reaction (anaphylaxis) can cause shock, a sudden drop in blood pressure and trouble breathing. In people who have an allergy, anaphylaxis can occur minutes after exposure to a specific allergy-causing substance (allergen). In some cases, there may be a delayed reaction or anaphylaxis may occur without an apparent trigger. If you're with someone having an allergic reaction with signs of anaphylaxis. . read more.

Cold or allergy: Which is it?

If you tend to get "colds" that develop suddenly and occur at the same time every year, it's possible that you actually have seasonal allergies. Although colds and seasonal allergies may share some of the same symptoms, they are very different diseases. Common colds are caused by viruses, while seasonal allergies are immune system responses triggered by exposure to an allergen. . read more.