According to MayoClinic.com, allergies never cause a fever. A fever is common if someone develops an infection or catches a viral infection. Certain allergic conditions, such as hay fever, can lead to complications that cause a fever, including a sinus or ear infection. Allergy symptoms such as sneezing, headaches and fatigue accompanied with a fever may be a sign of the common cold and should be evaluated by a physician.
Nasal Complications
Nasal allergies, or allergic rhinitis, can lead to nasal complications that result in a fever. Someone with allergic rhinitis will experience chronic congestion, post-nasal drip, a runny nose and sinus pressure because sinuses have become inflamed.
The swollen sinus cavity can trap excess mucus, creating an environment where bacteria and viruses can grow. Nasal allergies that go untreated can lead to a sinus infection, according to the National Institute of Allergy and Infectious Diseases.
A common symptom of a sinus infection is a low-grade fever below 102 degrees. The fever is attempting to ward off the invading bacteria or virus. Bacterial sinus infections are treated with antibiotics, while viral sinusitis is untreatable. OTC drugs are used to manage viral sinusitis symptoms, but the immune system needs to kill the virus for a cure.
Cough
A cough is a common denominator between allergies and the common cold. A cough resulting from an allergic reaction is because of restricted airways from an asthmatic reaction or it is the result of post-nasal drip, according to MayoClinic.com. A cough accompanied by a fever is a symptom of the common cold and needs to be evaluated by a doctor.
Sneezing
Sneezing is the result of sinus irritation that can result from allergies or a cold. Sneezing from an allergic reaction will never be accompanied with a fever. Allergic sneezing manifests itself with violent sneezing fits as soon as the person is exposed to the allergen, while sneezing from a cold is more sporadic and will produce thick, discolored nasal discharge. Sneezing from a cold will subside in 7 days, while sneezing from allergies can continue as long as the person is exposed to the allergen.
Sinus Headaches
Sinus headaches are common with allergy and fever symptoms. An allergic reaction can cause the sinuses to swell, placing excessive pressure on the head. This causes sinus pressure headaches that may be felt in the eyes, the upper teeth and cheekbones, according to the University of Maryland Medical Center. Headaches with a fever are an indication of a virus or bacteria and needs to be assessed by a physician.
