Allergies do not cause fevers, according to MayoClinic.com. Allergies can, however, give rise to other conditions that are sometimes accompanied by fever. Elevated body temperature can also be a symptom of illnesses similar to allergies. A doctor can determine the cause of fever and differentiate between the possible causes. If a doctor concludes the person has allergies, he will then likely search for a secondary infection causing the fever.
MedlinePlus states that an allergy occurs when someone's immune system encounters an allergen. The body attempts to fight off the substance, causing a chain reaction of symptoms, such as a runny nose, nasal congestion, sneezing, watery eyes and skin rashes. The most common causes of allergies are certain foods, medications and environmental factors, such as pollen, mold and dust.
A fever that develops from allergies is not caused by the allergic reaction, according to MayoClinic.com, but it is most likely a secondary infection caused by the allergic reaction. For example, someone who suffers from nasal allergies can develop chronic sinusitis, according to MedlinePlus.com. Chronic sinusitis can cause a fever in the body in order to fight the infection.
According to Dr.Spock.com, allergies and the common cold are difficult to differentiate. A person may think she is experiencing an allergic reaction, when she is actually fighting a cold. Major differences between allergies and the common cold exist and could be helpful in identifying which condition a person has. The common cold lasts for five to seven days, while allergies could last year-round. The common cold progressively gets worse, while allergies come on suddenly. The common cold produces thick, yellow nasal discharge and allergies produce thin, clear nasal secretions.
Treating allergies that result in a fever is based on the cause. Antibiotics are used for bacterial infections, decongestants are used to alleviate sinus congestion and pain relievers are used to provide relief from headaches and reduce the fever. If the fever is the result of a common cold, rest and drinking plenty of liquids is the best treatment, according to MayoClinic.com. A fever from a sinus infection will subside after the bacteria or virus is eliminated.
To prevent secondary infections and catching the common cold, treat allergies as soon as they appear, use nasal irrigation and use soap and hot water to wash hands regularly. Talk to a doctor to identify allergens and then avoid exposure to those substances that cause allergic reactions.