Cold vs Allergies: How to Tell the Difference

No, allergies do not cause fever. If you have a fever along with nasal symptoms, it's more likely a cold, flu, or sinus infection. However, severe allergies can cause sinus inflammation that leads to a sinus infection, which can cause fever. This is a complication of allergies, not the allergies themselves.

If you get sick at the same time each year (especially spring or fall), it's very likely seasonal allergies, not repeated colds. Tree pollen peaks in spring, grass pollen in summer, and ragweed in fall. Track your symptoms and timing — a clear annual pattern strongly suggests allergies.

Yes, you can have both simultaneously. In fact, allergies can make you more susceptible to colds because inflamed nasal passages are more vulnerable to viral infection. If your usual allergy symptoms suddenly include fever, body aches, or colored nasal discharge, you may have caught a cold on top of allergies.

Somewhat. Clear, thin, watery mucus suggests allergies. Yellow or green mucus usually indicates a cold or infection (white blood cells fighting the virus change the color). However, early-stage colds also produce clear mucus, so color alone isn't definitive. Consider other symptoms like fever and itchy eyes.

Yes, adult-onset allergies are common. You can develop allergies at any age, even if you never had them as a child. Moving to a new geographic area, hormonal changes, and immune system shifts can trigger new allergies. If you're suddenly experiencing seasonal symptoms as an adult, it could be newly developed allergies.