When you can’t stop sneezing and you feel hot and cold at the same time, you may wonder whether allergies are the culprit. However, allergies do not cause a fever. When you have a fever, it can arise from a variety of causes, such as COVID-19, influenza, or strep throat; but a fever is not due to allergies. Read on to learn how to spot allergies, and what you should do about them.
Can Allergies Cause a Fever or Chills?
A seasonal allergy to different types of pollen is often referred to as hay fever, or allergic rhinitis, but it is not to be confused with fever caused by a virus or bacterium.
Unlike a true fever, hay fever does not involve chills or a rise in body temperature, and is not caused by a bacterium or virus. Hay fever develops when your body encounters an allergen that your body perceives as a threat. If you have a fever while also experiencing an allergic reaction, you may be simultaneously sick from a viral or bacterial infection.
Hay fever can be triggered by:
- Tree, grass, or ragweed pollen
- Dust mites
- Cockroach droppings
- Animal dander
- Mold and fungi spores
Can Allergies Cause Other Flu-Like Symptoms?
While seasonal allergies do not cause a fever, they can come along with other flu-like symptoms such as a runny nose or an itchy, sore throat. When you encounter an allergen, your body responds by producing histamine, the chemical that causes allergic reactions.
A runny nose from allergies often produces thin, clear phlegm, whereas a runny nose from a virus will have thicker phlegm that is typically yellow. Allergies can also give you a sinus headache like those you experience when you are sick.
What Are the Common Symptoms of Allergies?
The kinds of allergy symptoms people experience will vary, depending on the type of allergy and the person. Seasonal allergies, such as those to pollen or mold, often occur at specific times of the year, such as the spring or late summer. An allergy to a dog or cat, however, can be triggered upon contact with dander.
Common seasonal allergy symptoms include:
- Watery, or itchy eyes
- Wheezing or coughing
- Itchy nose, eyes, or roof of the mouth
- Stuffy or runny nose
On the other hand, common food allergies such as reactions to tree nuts and shellfish may trigger more severe allergies, including anaphylaxis (anaphylactic shock). It’s important to recognize the symptoms of anaphylaxis because anaphylaxis is a medical emergency. Insect bites or stings, as well as some medications, can also trigger anaphylaxis in some people.
Symptoms of anaphylaxis:
- Swelling of the lips, tongue, or throat
- Tingling in the mouth
- The sensation that your throat is closing
- Feeling lightheaded or faint from low blood pressure
- Difficulty breathing
- Clammy skin
- Nausea or vomiting
- Swelling of the face and eyelids
- Skin reactions such as hives or a flushed face
What Could Be Causing Your Fever?
A fever is a body temperature of 100.4 degrees or higher. Becoming feverish is usually a sign your body is fighting an infection. Fevers can be caused by a variety of illnesses, from colds to flu, COVID-19, earaches, strep throat, bronchitis, mononucleosis, and urinary tract infections.
Signs you may have a fever:
- Body temperature of 100.4 or higher
- Body aches
- Chills or shivering
- Feeling hot and cold at the same time
- Intermittent or constant sweating
- Flushed skin
How to Manage a Fever?
If your fever is lower than 102, there is no need to take a fever-reducing medicine. A mild fever can be treated at home with rest and staying hydrated.
However, if your fever is 102 or above you should treat it with an OTC fever-reducing medication such as ibuprofen (Advil), acetaminophen (Tylenol), or naproxen (Aleve). Additionally, If your fever reaches 103 or higher you should contact a medical professional right away.
There are several ways doctors may diagnose allergies. Typically, a doctor will ask you questions about your symptoms and physically examine you for allergy symptoms.
A doctor may also request that you use a food diary to document the foods you eat, to help determine any triggers for food allergies. In some cases, you may also be asked to try an elimination diet to detect food intolerances.
There are also other means for diagnosing allergies:
- Blood test: With a blood test, an antibody called immunoglobulin E (IgE) will be measured. An antibody is a protein produced in responses to substances the body considers harmful, such as bacteria or viruses. Some people with allergies may have a higher level of IgE antibodies.
- Skin prick test: This common type of allergy test involves pricking the skin with tiny amounts of protein found in common allergies such as cat dander, mold, and pollen. If you are allergic to one of the proteins tested, you will develop a hive on your skin in that area.
When to See a Doctor?
You should see a doctor if you are experiencing bothersome allergy symptoms, such as nasal congestion, a runny nose, a cough, or watery eyes. Sometimes OTC antihistamine allergy medications, such as Claritin and Zyrtec are enough to relieve allergy symptoms, but you should see a doctor if you have:
- Ongoing symptoms that aren’t relieved by OTC allergy medicines
- Trouble sleeping due to nasal congestion or wheezing
- Difficulty staying asleep due to congestion
- Noticeable allergy symptoms, such as sneezing during specific times of the year, or in the presence of pets
- Asthma; allergies can be a complication for people with asthma.
Get Help From an Online Doctor!
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Allergic reactions are not to be confused with fevers caused by viral or bacterial infections. Allergic reactions may include some cold and flu-like symptoms, but those reactions are triggered by common allergens such as pollen, dust, mold, or animal dander.
More severe allergic reactions, caused typically in susceptible people by exposure to shellfish, nuts, or insect stings, can result in anaphylactic shock, a medical emergency.
If you have an elevated temperature of 100.4 or greater, you have a fever, but not one that is due to allergies. If you are concerned about allergies or a fever, it’s time to contact a doctor.
- AAFA. Asthma and Allergy Foundation of America. (n.d.). Retrieved August 19, 2022, from https://www.aafa.org/allergy-symptoms/
- Anaphylaxis. American Academy of Allergy Asthma & Immunology. (n.d.). Retrieved August 17, 2022, from https://www.aaaai.org/Tools-for-the-Public/Conditions-Library/Allergies/anaphylaxis
- Becker, J. H., & Wu, S. C. (2010). Fever–an update. Journal of the American Podiatric Medical Association, 100(4), 281–290. https://doi.org/10.7547/1000281
- Nadolpho. (2022, April 13). Allergies – how to manage and treat allergies: Acaai Patient. ACAAI Public Website. Retrieved August 19, 2022, from https://acaai.org/allergies/
- Ogoina D. (2011). Fever, fever patterns and diseases called ‘fever’–a review. Journal of infection and public health, 4(3), 108–124. https://doi.org/10.1016/j.jiph.2011.05.002
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DrHouse articles are written by MDs, NPs, nutritionists and other healthcare professionals. The contents of the DrHouse site are for informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. If you are experiencing high fever (>103F/39.4C), shortness of breath, difficulty breathing, chest pain, heart palpitations, abnormal bruising, abnormal bleeding, extreme fatigue, dizziness, new weakness or paralysis, difficulty with speech, confusion, extreme pain in any body part, or inability to remain hydrated or keep down fluids or feel you may have any other life-threatening condition, please go to the emergency department or call 911 immediately.