When to Use Auto-Injectors You can’t predict allergic reactions. They can be mild one time and serious the next. An attack can quickly become intense, sometimes leading to anaphylaxis -- a severe, often life-threatening reaction. An auto-injector -- such as EpiPen or Auvi-Q -- can treat extreme allergic reactions with an early, life-saving dose of epinephrine.

Epinephrine is adrenaline, a hormone your body naturally produces. Among other things, it can help improve breathing, raise blood pressure that’s dropping, and reduce swelling.

When you or a loved one has an allergic reaction, it’s common to wonder if the shot is needed. Experts say even if there's any doubt, use the device. It’s much more dangerous not to get epinephrine when you’re having a severe reaction than to get a dose you don’t really need.

Slideshow: Top Items for Your Allergy Relief Kit