ask a doctor

Signs and symptoms

  • Altered mental status.
  • Itchy, watery eyes.
  • Runny or stuffy nose.
  • Breathing difficulties.
  • Wheezing, caused by bronchiole lining constriction and inflammation.
  • Stridor or crowing, caused by swelling and constriction of the upper airway.
  • Swelling.
  • Weak and rapid (thready) pulse.
  • Tachycardia.
  • Low blood pressure.
  • Irregular pulse.
  • Shock / hypoperfusion.
  • Abnormal skin coloration.
  • Hives, blotches over skin.
  • Nausea / vomiting.
  • Abdominal problems such as cramping, diarrhea, loss of bowel control.


  • For mild reactions, maintain airway and provide oxygen. Realize that mild reactions can progress to severe anaphylaxis.
  • Suction any secretions.
  • Oxygen administration.
  • PPV if necessary.
  • Epinephrine injection.
  • Metered dose inhaler prescribed for asthma patients.
  • Endotracheal intubation, which maintains an airway that may otherwise shut off completely.

Medical conditions and mechanisms

  • Anaphylaxis: antigen attaches to antibodies located on MAST cells and basophils, which causes the cell membranes to breakdown and release chemical mediators such as histamine. The body responds with bronchoconstriction, increased mucus production, vasodilation, and increased capillary permeability. This narrows airways, occludes smaller bronchioles, causes swelling and lowers blood pressure. The patient may go into shock.
  • Mild allergic reactions can progress to severe anaphylaxis.
  • Allergic reactions can be caused by venum from bites or stings, foods, pollen, medications, chemicals, and latex. Exercising right after exposure of allergins can accentuate anaphylaxis.


  • Anaphylaxis: also called anaphylactic shock, is a severe allergic reaction that is life threatening.
  • Anaphylactoid reaction: same as anaphylaxis, except there is no prior exposure or sensitization.
  • Sensitization: the body's response to encountering an antigen, whereby antibodies attach to mast cells and basophils. So, if the antigen is encountered again, the mast cells and basophils will release histamine, which cause an allergic reaction.
  • Histamine: chemical that causes allergic reactions, such as bronchoconstriction, vasodilation, and capillary leakage.
  • Urticaria: hives on skin.
  • Pruritus: itching.