The symptoms of anaphylaxis and anxiety/panic attacks can overlap and can be difficult to distinguish. Both can cause shortness of breath, chest tightness, heart palpitations, and a sense of being unable to catch your breath. With anaphylaxis, you may also experience hives and swelling. Also, the symptoms of anaphylaxis usually come on suddenly and can be attributed to a specific trigger, while the symptoms of anxiety/panic attacks tend to build up over time. Anaphylaxis can be life-threatening, so it's important to seek medical help right away.