According to MayoClinic.com, allergies never cause a fever. If a low fever develops as a result of an allergic reaction, it is from a secondary infection, such as sinusitis, bronchitis or an ear infection. Allergies are commonly confused with the common cold because their symptoms are very similar. If someone develops typical allergy symptoms suddenly with a fever, she may have caught a cold, unrelated to allergies. A doctor will provide a proper diagnosis.
Cause
When someone has an allergic reaction, chemicals are released in the body by the immune system to fight off the allergen. This causes inflammation and irritation in the sinuses, airways and the skin, according to MedlinePlus. The inflammation leads to swollen membranes that obstruct the person's ability to breathe and drain mucus properly. The trapped mucus can grow bacteria, leading to a secondary infection.
Symptoms
MedlinePlus states that symptoms of allergies are a runny nose, nasal congestion, sneezing, watery eyes, throat irritation, hives and breathing difficulty. If more symptoms appear, such as thick, yellow mucus, low fever and chills, a secondary infection has most likely set in. Other symptoms such as difficulty breathing, mental confusion or severe head pain may be a sign or a more serious condition.
Types
The most common secondary infections caused by allergies are sinusitis, bronchitis and ear infections. Sinusitis is an infection in the sinus cavity, according to the Asthma and Allergy Foundation of America. A sinus infection is typically left untreated and clears up on its own with over-the-counter medications, such as decongestants. If it progresses or becomes worse, a doctor may recommend antibiotics. Bronchitis is an infection in the bronchial tubes, commonly associated with allergy-induced asthma. Ear infections are a result of blocked inner-ear tubes that normally drain fluid.
Treatment
Depending on the type of infection, the treatment will vary. If allergies are the primary cause of the secondary infection, antihistamines can be taken to alleviate allergy symptoms. Attempt to avoid all known allergens and take an antihistamine. Antihistamines will maintain a healthy level of histamine in the blood stream, preventing inflammation and irritation, according to FamilyDoctor.org. To treat the low fever, take an over-the-counter pain reliever/fever reducer. Talk with a doctor about the best pain reliever based on medical history.
Considerations
MayoClinic.com states that allergies will come and go based on exposure to allergens, while the common cold will develop slower and symptoms will only last for around 5 days. Talk to the doctor at the first signs of a fever with allergy-like symptoms.
