When inflammation spreads from a localized area of one organ (like the skin) to other organ systems in the body, it's known as a systemic reaction. The inflammation can be from toxins, allergies or infections.

How long can a systemic reaction last?

This early or immediate response peaks at about 15 minutes and symptoms fade within 90 minutes. Sometimes, the immediate effects are followed by a late-phase reaction with symptoms occurring about four to six hours later and lasting up to a day.

What are the 4 types of allergic reactions?

Allergists recognize four types of allergic reactions: Type I or anaphylactic reactions, type II or cytotoxic reactions, type III or immunocomplex reactions and type IV or cell-mediated reactions.