90% in 4 hours. The so called biphasic anaphylaxis is where the symptoms recur after having been treated initially. So the patient is treated appropriately initially, but the anaphylaxis comes back. Biphasic anaphylaxis is more common if the initial therapy is delayed or if the initial presentation is more severe. For this reason the patient may be observed in the er for 4 hours in some cases.
A few hours. You typically have severe allergic reactions to bee stings within a few minutes of exposure but you could have a reaction a few hours after the event. Anaphylaxis is a life-threatening condition and needs emergency treatment and evaluation by an allergist.
BEE Aware. True anaphylaxis is a fairly rapid event but can evolve over time and become more serious. In younger children abdominal pain and nausea are actually fairly common and more serious as internal organ failure can occur with this condition. If you have a first time reaction to a sting beyond a local reaction, that involves a personal sense of doom, dizziness, or confusion get help right away!
Rapid onset. Anaphylaxis is characterized by a defined exposure to a potential trigger, followed by rapid onset, evolution, and resolution of symptoms and signs within minutes to hours. There is a biphasic form involving a recurrence of symptoms 8-10 hours after the apparent resolution of the initial episode with no further exposure to the trigger. Protracted form can last for hours, days, or weeks.