Is Fever a Symptom of Allergies?

By Jennifer Nadel, MD
Medically reviewed checkmarkMedically reviewed
April 26, 2022

When you are sick, it can be challenging at times to figure out what exactly you have.

Symptoms of different illnesses often overlap. Then add in the fact that some names can be confusing. 

For example, take hay fever. This condition not only isn’t necessarily triggered by hay, it also doesn’t cause fever. 

To help you understand fevers, hay fever, and seasonal allergies, in this article, I’ll first detail common allergy symptoms.

Then I’ll explain what else can cause fever and allergy-like symptoms.

I’ll also share tips for managing a fever, how doctors diagnose allergies, and when to see a medical provider about symptoms of allergies.

Common Allergy Symptoms

Seasonal allergies can cause a wide range of symptoms, including:

In some cases, irritation from postnasal drip can also cause a sore throat and mild cough.

If you have a worsening cough, fever, muscle aches, joint pain, or diarrhea, it is not from seasonal allergies.

These symptoms are more indicative of an infection.

Hay fever symptoms

Hay fever is another term for allergic rhinitis. It is caused by seasonal allergy symptoms.

With hay fever, you may notice:

  • Itchy nose, eyes, mouth, throat, or skin
  • Reduced ability to smell
  • Feeling of clogged ears
  • Runny nose and nasal congestion
  • Sneezing
  • Watery eyes
  • Sore throat
  • Puffiness under the eyes
  • Fatigue
  • Mild headache
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What Can Cause a Fever and Allergy-Like Symptoms?

Although seasonal allergies are sometimes referred to as “hay fever”, fever is not an actual symptom.

If you have allergy-like symptoms and a fever, you most likely have a viral or bacterial infection.

Most commonly, these may include the flu, a cold, or COVID-19.

Flu

Flu symptoms can include:

Sinusitis

A sinus infection, also known as sinusitis, can be caused by a virus or bacteria.

Sometimes a sinus infection can develop after seasonal allergy symptoms.

Sinus infections that are caused by viruses or bacteria tend to have the same symptoms, such as:

  • Postnasal drip
  • Congestion
  • Pain in the sinuses around the cheeks and forehead
  • Yellow or green nasal discharge
  • Fever
  • Runny nose or congestion
  • Sore throat
  • Cough
  • Bad breath
  • Toothaches from sinus pressure
  • Fatigue

Common cold

Symptoms of the common cold include:

  • Runny nose or congestion
  • Yellow or green nasal discharge
  • Sore throat
  • Cough
  • Hoarse voice
  • Sneezing
  • Headache
  • Mild body aches
  • Low-grade fever
  • General feeling of unwellness

Tips for Managing a Fever

The average normal body temperature is 98.6º F (37º C).

A fever is a body temperature of 100.4° F (38° C) or greater.

Many things can raise the body’s temperature and cause a fever.

Whether a fever is cause for concern and requires treatment depends on how high the temperature is and any other symptoms.

If you have a fever, you can manage it in the following ways:

  • Get plenty of rest. Your immune system is fighting an infection, and rest supports your body’s recovery.
  • Take over-the-counter pain relievers. These can help to reduce fever and provide comfort for other symptoms. Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) are the most common fever reducers.
  • Stay hydrated. An increased body temperature from fever can cause dehydration and increase your body’s need for fluids. Drink water and non-caffeinated beverages throughout the day. You can also drink electrolyte beverages like sports drinks to help replenish electrolytes, which help your cells manage water balance.

If you experience a fever of 104° F (40° C) or greater, or you have a fever that does not resolve on its own after a few days, seek medical care.

Diagnosing an Allergy

Allergies are caused by your immune system’s over-response to a trigger.

With seasonal allergies, the trigger is commonly pollen from trees, grass, or plants.

Things like pet dander, dust mites, and mold are common triggers of environmental allergies.

When exposed to a trigger, the immune system produces histamine, a compound that leads to allergy symptoms such as sneezing, itchy eyes, runny nose, and rash.

A doctor or medical provider can run tests to diagnose allergies. These tests include: 

  • Skin prick test: The healthcare provider puts tiny drops of various allergens on your skin. Then they lightly prick or scratch the skin and wait a few minutes to see if you have an allergic reaction. 
  • Patch test: Similar to a prick test, the healthcare provider puts small amounts of different allergens on your skin. But rather than scratching the skin, they cover these spots with patches. After 48 or more hours, you return to the provider’s office to check for any reactions.
  • Blood test: The doctor takes a blood sample to check for the presence of antibodies (called immunoglobulin E) that the body produces in response to allergens.

Doctors or medical providers may use more than one method to test or confirm more complicated allergies.

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When to See a Medical Provider

Seasonal allergies are common, but they don’t cause fevers.

If you have a fever along with allergy symptoms, you don’t necessarily need medical care right away.

But if your symptoms don’t improve or they worsen, see a doctor. You could have a viral or bacterial infection.

Also, if you experience any of the following, seek emergency medical care: 

  • Fever greater than 103º F
  • Dizziness
  • Problems thinking clearly
  • Headache
  • Stiff neck
  • Difficulty urinating
  • Yellowing of the skin

How K Health Can Help

Did you know you can get affordable primary care with the K Health app? Download K to check your symptoms, explore conditions and treatments, and if needed text with a provider in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

Frequently Asked Questions

Can allergies cause low grade fever?
Seasonal allergies do not cause any type of fever. However, a sinus infection that occurs as a result of allergies could lead to a fever. Other infections can also cause fevers.
Is it possible to have both a head cold and allergies at the same time?
Yes, you can get a head cold, which is caused by a virus, at the same time you are experiencing seasonal allergies. The cold will clear up after a week or two, but seasonal allergies will persist as long as the trigger is around.
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Jennifer Nadel, MD

Dr. Jennifer Nadel is a board certified emergency medicine physician and received her medical degree from the George Washington University School of Medicine. She has worked in varied practice environments, including academic urban level-one trauma centers, community hospital emergency departments, skilled nursing facilities, telemedicine, EMS medical control, and flight medicine.