Anaphylactic shock is an immediate allergic response. Why is anaphylactic shock a medical emergency?

Severe allergic response causes fluid loss from the blood, breathing difficulty and therefore, is life threatening.

Explanation:

The anaphylactic shock results from the type I allergic reactions during which the presence of an allergen triggers a severe response. It occurs since IgE antibodies are already present in the body. There is a release of histamine and other vasodilators. Vasodilation and increased permeability of the blood capillaries result in the loss of fluid from the blood. Constriction of airways of the lungs causes difficulty in breathing and weakens the heartbeat. Therefore, severe fluid loss from blood and constricted airways make it life-threatening.

You will lose blood, and not be able to lead, which could result in death.