Can Allergies Cause A Fever?

If you have seasonal allergies, you know that allergies share many of the same symptoms as the common cold or even the flu. Sneezing, coughing, runny nose, and congestion are all typical allergy symptoms that can often overlap with other common illnesses (via Prevention). Unlike a cold or the flu, however, a fever is not a symptom of seasonal allergies.

That's because allergies are the result of your immune system's response to allergens like pollen and dust mites, while a fever is often an indication of a bacterial or viral infection. "Seasonal allergies should not cause a fever," according to Dr. Jessica Hui, an allergy and immunology physician at National Jewish Health in Denver. "Many of us have heard someone sneeze and then say, 'It's just my allergies' when they're actually sick with the common cold." If your temperature rises above 100.4 degrees, you should make an appointment with your doctor. You may have an illness that requires antibiotics or additional treatment.

However, it is possible for your allergies to cause an infection, which may lead to a fever (via Healthline). In fact, any condition that causes congestion can potentially result in a bacterial infection. When you develop congestion from allergies or the common cold, your nose and sinuses can become swollen and inflamed, which can prevent the mucus in your sinuses from draining properly (via WebMD).

This can lead to a buildup of mucus in your sinuses, which can become the perfect breeding ground for harmful bacteria to grow and cause an infection. This is known as sinusitis or a sinus infection. While sinusitis is a separate diagnosis, it is often triggered by a cold and allergies, and the infection it causes can potentially result in a fever.

If you have allergies and think you might be developing a sinus infection, you should contact your doctor to discuss treatment options. They might recommend nasal sprays or over-the-counter medications like decongestants or antihistamines. However, if your infection is more severe, they may prescribe a round of antibiotics.