Why Your Body Temperature Spikes During Allergy Season

Health Points

• Allergies themselves don’t cause fevers, but complications like sinus infections can trigger elevated body temperature
• A fever above 100.4°F with allergy symptoms typically signals an infection requiring medical attention
• Natural antihistamines and staying hydrated help manage allergy symptoms without medication side effects

When spring arrives and the sniffles start, many Americans wonder whether that warm feeling is just another allergy symptom. The answer might surprise you—and it’s important to know the difference.

Allergies trigger your immune system to overreact to harmless substances like pollen or pet dander. While this response causes familiar symptoms like sneezing, itchy eyes, and congestion, it doesn’t directly cause fever.

“True allergies don’t cause fevers,” explains Dr. Sarah Mitchell, an allergist practicing in Phoenix. “When we see an elevated temperature alongside allergy symptoms, we’re usually looking at a secondary infection.”

The confusion stems from how similar allergies and infections can feel. Both can make you feel miserable with a stuffy nose, headache, and general fatigue. The key difference lies in your thermometer reading.

A normal body temperature ranges from 97°F to 99°F. Anything above 100.4°F indicates a fever—and that means something beyond allergies is happening in your body.

When allergies cause nasal passages to swell and mucus to accumulate, bacteria can multiply in those warm, moist spaces. This creates the perfect environment for sinus infections, which do cause fever.

“Think of allergies as opening the door for infections,” says Dr. Mitchell. “The inflammation they cause makes it easier for viruses and bacteria to take hold.”

Other signs that you’re dealing with an infection rather than just allergies include thick, colored nasal discharge (yellow or green), facial pain or pressure, and symptoms lasting more than 10 days. Allergy symptoms tend to remain consistent and clear, while infection symptoms often worsen over time.

For those managing seasonal allergies, prevention remains the best strategy. Keeping windows closed during high pollen counts, using HEPA filters in your home, and showering before bed to remove pollen from hair and skin can significantly reduce symptoms.

Natural remedies also offer relief for many people. Local honey, consumed regularly before allergy season begins, may help your body build tolerance to local pollen. Quercetin, a natural compound found in apples, onions, and berries, acts as a natural antihistamine without drowsiness.

Staying well-hydrated thins mucus and helps your body flush out allergens more effectively. Warm liquids like herbal tea or broth provide additional comfort while supporting your immune system.

When fever does develop alongside allergy symptoms, it’s time to consult your healthcare provider. They can determine whether you need antibiotics for a bacterial infection or if rest and supportive care will suffice.

“Don’t try to power through a fever,” advises Dr. Mitchell. “Your body is telling you it’s fighting something more serious than pollen.”

For those over 40, paying attention to these signals becomes even more important. Our immune systems change with age, and what once felt like a minor inconvenience can develop into something requiring medical intervention.

Understanding the difference between allergy symptoms and fever helps you respond appropriately. While allergies themselves won’t spike your temperature, the complications they create certainly can—and knowing when to seek help makes all the difference in recovering quickly and safely.