Logo

About Allergies

Allergic Reactions

Signs and Symptoms of Anaphylaxis

An allergic reaction usually happens within minutes after being exposed to an allergen, but sometimes it can take place several hours after exposure. A reaction can involve any of these symptoms, and a person could have one or more of these symptoms regardless of the allergen:

  • Skin system: hives, swelling, itching, warmth, redness, rash
  • Respiratory system (breathing): coughing, wheezing, shortness of breath, chest pain/tightness, throat tightness, hoarse voice, nasal congestion or hay fever-like symptoms (runny itchy nose and watery eyes, sneezing), trouble swallowing
  • Gastrointestinal system (stomach): nausea, pain/cramps, vomiting, diarrhea
  • Cardiovascular system (heart): pale/blue colour, weak pulse, passing out, dizzy/lightheaded, shock
  • Other: anxiety, feeling of “impending doom”, headache, uterine cramps, metallic taste

The most dangerous symptoms of an allergic reaction are:

  • Trouble breathing caused by swelling of the airways (including a severe asthma attack for people who have asthma)
  • A drop in blood pressure causing dizziness, light-headedness, feeling faint or weak, or passing out.
  • Both can lead to death if untreated.

Remember:

  • Do not ignore early symptoms.
  • Always take a possible reaction seriously and act quickly.
  • Not every reaction will always look the same; a person can have different symptoms each time.
  • Anaphylaxis can occur without skin symptoms or hives.
  • A child may describe their symptoms differently than an adult: for example “my throat is tingly” or “my tongue feels scratchy”.