The main difference

Both allergies and sinus infections can feel miserable. However, these conditions aren’t the same thing.

Allergies occur as a result of your immune system’s reaction to certain allergens, such as pollen, dust, or pet dander. A sinus infection, or sinusitis, occurs when your nasal passages get infected.

Both conditions can cause nasal inflammation, along with related symptoms, such as congestion and stuffy nose.

Still, these two conditions have different causes and symptoms. Explore the differences between allergies and sinus infections so that you can determine the likely cause of your symptoms and seek the appropriate treatment for relief.

Allergies can develop at any point in your life. While allergies tend to come up during childhood, it’s possible to develop allergies to new substances as an adult.

This type of reaction is caused by a negative response to a substance. Your immune system responds by releasing a chemical called histamine, which can then cause symptoms such as headache, sneezing, and congestion. It’s also possible to feel foggy and develop a skin rash.

Severe allergies can lead to a cold-like condition called allergic rhinitis. With allergic rhinitis, you can have the above symptoms as well as itchy eyes. This itchiness is one of the key distinguishing factors between allergies and sinusitis.

A sinus infection, on the other hand, occurs when your nasal passages become inflamed. Sinusitis is most often caused by viruses. When the nasal cavity gets inflamed, mucus builds up and gets stuck, further compounding the problem.

Along with nasal congestion and headache, sinusitis causes pain around your cheeks and eyes. Sinus infections also cause thick, discolored mucus, and bad breath.

Compare the following symptoms to see if you have allergies or a possible sinus infection. It’s also possible to have both conditions at the same time.

AllergiesSinus infection
Nasal congestionXX
Pain around cheeks and eyesX
Itchy, watery eyesX
Thick, yellow/green dischargeX
Difficulty breathing through noseXX
Unable to blow your noseX
Tooth painX
Bad breathX

Allergy and sinus infection treatments share some similarities and differences. If you have severe congestion with either, then an over-the-counter (OTC) or prescription decongestant can help by breaking up mucus in your nasal cavities.

Allergies are also treated with antihistamines. These block the immune system’s histamine-producing response whenever you encounter an allergen. As a result, you should experience fewer symptoms.

Some antihistamines, such as Benadryl, are usually taken for short-term relief. Long-term (chronic) or severe allergies benefit more from daily treatments, such as Zyrtec or Claritin. Some of these antihistamines also have an added decongestant to them.

Allergy medications won’t get rid of sinus infections, though. The best ways to clear up viral infections are with the following methods:

  • Rest as much as you can.
  • Drink clear fluids, such as water and broth.
  • Use a saline mist spray to hydrate nasal passages.
  • Continue taking allergy meds, if you did so previously.

Viral infections can’t be treated with antibiotics. However, if your doctor thinks your sinus infection is bacteria-related, they may prescribe an antibiotic. You’ll need to take the full prescription, even if you start feeling better within a day or two.

You can help prevent a sinus infection in much the same way as you would prevent catching cold and flu viruses. Get plenty of sleep and stay hydrated during cold and flu season. Also, ask your doctor about supplements such as vitamin C to help boost your immune system. Frequent handwashing is also a must.

You can’t, on the other hand, fully prevent allergies. However, it may be helpful to avoid the substances you know you’re allergic to as often as you can.

For example, if you have seasonal allergies to pollen, avoid going outdoors when the counts are at their highest. You’ll also want to wash your hair before bed after being outside and keep your windows closed when pollen counts are high.

Dust mite allergies can be alleviated with weekly house cleanings and bedding washes. If you have pet dander allergies, make sure your furry loved ones don’t sleep in bed with you and wash your hands after petting them and before touching your face.

Treating your allergy symptoms early on can also help prevent your allergies from getting out of control. If you know you’re allergic to pollen and that pollen season is around the corner, start taking your antihistamine ahead of time.

Also ask your doctor about recommendations for other medications you can take as preventive measures. You may be a good candidate for allergy shots, which can lessen the way your body reacts to allergens over time.

You don’t necessarily have to see your doctor for your allergies. The exception is if you’ve never been diagnosed with allergies before or if your allergies seem to be getting worse.

You should also see your doctor if your OTC antihistamines aren’t working. They might recommend prescription medications instead. If your allergies have you particularly congested, they might also prescribe a decongestant.

Since sinus infections are caused by viruses, antibiotics don’t generally help. However, if your symptoms worsen or last longer than two weeks, you should see your doctor for some relief.

Allergies and sinus infections can have similar symptoms. One of the key differences is the itchiness of your eyes and skin that can occur with allergies, as well as the thick, yellow or green nasal discharge that’s notable with sinusitis.

Another difference is the timeline. Allergies can be chronic or seasonal, but avoidance and medication can help alleviate your symptoms. A sinus infection can take several days to improve, but sometimes you’ll need prescription medications until you start feeling better at all. This all depends on the severity of the virus.

With some of these key differences in mind, you may be able to figure out whether you’re dealing with allergies or sinusitis and take the necessary steps to start feeling better.

When in doubt, see your doctor. You should also make an appointment if your symptoms worsen or fail to improve despite home treatments.