It is common to confuse allergy symptoms with those of infections, especially when feeling unwell. Many people wonder if their allergies could be the cause of a fever. This article aims to clarify the relationship between allergies and elevated body temperature, helping to distinguish between allergic reactions and other illnesses.
Allergies and Body Temperature
Allergies do not cause a fever. An allergic reaction involves the immune system overreacting to a harmless substance, an allergen, by releasing chemicals like histamine. This process leads to localized inflammation in areas such as the nasal passages, skin, or airways, resulting in symptoms like sneezing or itching. This immune response does not trigger the systemic increase in core body temperature that defines a fever. The term “hay fever” is a misnomer, as it is not associated with a fever.
Common Symptoms and Misconceptions
Allergy symptoms can mimic those of a common cold or other mild infections, leading to confusion. Common allergy symptoms include sneezing, a runny or stuffy nose, watery and itchy eyes, and sometimes a sore throat or fatigue. These symptoms overlap significantly with those experienced during a viral infection. This symptom overlap, combined with a general feeling of being unwell, can lead to the mistaken belief that allergies cause fever.
When Fever Appears
Fever is a temporary increase in the body’s set-point temperature, signifying that the body is actively fighting off an infection. This response is triggered by pathogens like viruses or bacteria, or by significant inflammation. Common conditions that cause fever include the common cold, influenza, bronchitis, or sinus infections.
When an infection occurs, immune cells release specific chemicals called pyrogens, such as interleukins, which travel to the hypothalamus in the brain. The hypothalamus, acting as the body’s thermostat, then resets to a higher temperature, prompting the body to generate and conserve heat through mechanisms like shivering or constricting blood vessels. This elevated temperature can help inhibit pathogen growth and enhance immune cell function.
Next Steps and Medical Guidance
If you experience allergy-like symptoms along with a fever, it is important to monitor your condition closely. Consider if you have been exposed to others who are ill, as allergies themselves do not cause fever, but they can sometimes make one more susceptible to infections. Seek medical advice if the fever is high, persistent (lasting more than three days), or accompanied by severe symptoms such as difficulty breathing, severe body aches, a stiff neck, or mental confusion. A healthcare professional can help differentiate between an allergic reaction and an infection, providing an accurate diagnosis and appropriate treatment.