— DEAR MAYO CLINIC: I have long suffered from allergies. But there have been times when I haven’t been sure if my symptoms are really from my allergies or may be caused by a sinus infection instead. How can I tell the difference?
ANSWER: Allergies and sinus infections are often mistaken for one another. But they are two separate conditions. By paying close attention to the specific symptoms you have, you can usually identify which one is more likely to be causing the problem.
A sinus infection, also called sinusitis, affects the cavities around your nasal passages. The infection causes your sinuses to become inflamed and swollen. The swelling makes it hard for your sinuses to drain, and mucus builds up. You become congested and have trouble breathing through your nose. Sinusitis often causes thick yellow or green nasal discharge. A sore throat, cough or headache, as well as pressure or tenderness around your eyes, cheeks, nose or forehead, may also accompany sinusitis.
In most cases, viruses cause sinusitis. These viral infections usually go away on their own within a week to 10 days. Self-care measures such as extra rest and fluids along with over-the-counter pain relievers and decongestants can help. When sinusitis is caused by bacteria, the infection may not require treatment, either. But if it is persistent or severe, then antibiotics — such as amoxicillin, doxycycline and others — may be used to treat the infection.
Allergies can produce many of the same cold-like symptoms as a sinus infection, including sinus pressure, a runny nose and congestion. But the condition itself, called allergic rhinitis, is different. It is caused by an allergic response to allergens, such as pollen, dust mites or pet dander. This reaction happens when your immune system releases chemicals, such as histamine, into your bloodstream. These immune system chemicals lead to your allergy symptoms.