Can Allergies Cause a Fever?


Allergy symptoms typically include sneezing, watery eyes, a runny nose, or even a skin rash. Some allergens can even trigger allergic reactions known as anaphylaxis that are medical emergencies.

But can allergies cause a fever? Generally, no. Sometimes, however, allergy symptoms can make you vulnerable to a bacterial or viral infection. And a bacterial or viral infection can lead to a fever, so you can indirectly blame the fever on your allergy.

Common allergy symptoms

Your symptoms depend on the cause of the allergy, known as an allergen. When you’re allergic to something, whether it’s dust, peanuts, or something else, your body reacts to the allergen by producing a chemical called a histamine.

Depending on the individual and the particular allergen, symptoms can include:

  • runny nose
  • itchy or watery eyes
  • sneezing
  • coughing
  • headache or sinus pain
  • sore throat
  • wheezing
  • post nasal drip

Nausea and diarrhea are common symptoms of certain food allergies. Swelling and skin rash are also signs of an allergic reaction.

Despite its name, hay fever usually doesn’t include a fever. Hay fever, known clinically as allergic rhinitis, is a broad term used to describe an allergy to things in the environment such as pollen, mold spores, and grass.

When an allergic reaction is so severe that your breathing is jeopardized and you lose consciousness or are at risk of losing consciousness, it’s called anaphylaxis. Anaphylaxis is a medical emergency that requires immediate medical attention.