Allergies or Sinus Infection: What Are the Differences?

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Allergies and sinus infections are closely related conditions that have overlapping symptoms. Both allergies and sinus infections are common. Approximately 50 million Americans suffer from allergies including food allergies, allergic eczema (skin problems related to allergies), and allergic rhinitis. Untreated allergies can lead to sinus infections. Sinus infections, also called sinusitis, affect approximately 31 million Americans every year. Sometimes it can be difficult to tell the difference between the two illnesses.

This article will discuss the differences between allergy and sinus infection symptoms and how to tell the difference.

a sick woman blowing her nose

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Symptoms

Allergies

Symptoms of an acute allergy attack may include:

  • Itching, especially of the eyes or nose
  • Sneezing
  • Coughing
  • Watery eyes
  • Runny nose (usually mucus appear clear or watery)
  • Skin rashes (hives)

Symptoms of chronic allergies may include:

  • Congestion
  • Headache
  • Sore throat
  • Postnasal drip
  • Decreased sense of smell
  • Fatigue
  • Dark circles under the eyes

Anaphylaxis

Anaphylaxis is a life-threatening allergic reaction, which can cause the airway to swell and restrict, making it difficult to breathe. If you have symptoms of anaphylaxis, call 911 or go to an emergency room immediately.

Sinus Infections

Symptoms of a sinus infection may include:

  • Postnasal drip
  • Runny nose with mucus that is not clear but yellow or green in color
  • Congestion
  • Pain and tenderness in the face (often around the eyes and nose)
  • Headaches
  • Toothaches
  • Coughing
  • Fever
  • Fatigue
  • Bad breath

Differing Symptoms

Several key symptoms can help you to determine if you are suffering from allergies or a sinus infection. For example, allergies usually do not cause fever, toothaches, and facial pain, and a rash or hives are unlikely to occur from a sinus infection.

Causes

Allergies

Allergies are the result of an overreaction by your immune system in response to a specific substance (called an allergen). During this process, a substance called histamine is released, which is largely responsible for many of the symptoms associated with allergies.

Sinus Infection

The sinuses are hollow cavities in the skull which are lined with mucous membranes. A sinus infection can occur when these cavities become inflamed (swollen) or blocked.

Infections can be caused by different kinds of germs including bacteria, fungi, and viruses. Sinus infections frequently occur after you've suffered congestion from a recent cold or allergies.

Sinus infections are also more likely to occur in people who have a deviated septum, nasal polyps, or a weakened immune system.

Diagnosis

Allergies

Allergies are often diagnosed by a specialist called an immunologist, although allergy testing may be ordered or performed by other types of healthcare providers as well.

Tests used to diagnose allergies include:

  • Blood tests (IgE testing)
  • Skin scratch testing
  • Intradermal allergy tests

Skin and intradermal testing involves exposing you to potential substances (allergens) and then monitoring your reaction to the substance.

Sinus Infection

To diagnose a sinus infection, a healthcare provider will usually start by asking you about your symptoms and conducting a physical examination, checking for swelling or blockage in the nose and throat using a tool called an endoscope.

Sometimes a CT scan is used to help with diagnosis.

Treatment

Allergies

Identifying the substance you are allergic to and avoiding it is an essential part of managing allergies.

Medications to control symptoms or alter the immune response are commonly used and may include:

Sinus Infection

If your sinus infection was caused by untreated allergies, using the treatments outlined above for allergies is an important component of treating a sinus infection.

Other various treatments are used for managing symptoms of a sinus infection, as well as any underlying causes of infection.

Treatments for managing symptoms of a sinus infection include:

Treatments used to address the root cause of the infection include:

  • Antibiotics
  • Leukotriene antagonists
  • Steroid nasal sprays
  • Surgery to correct a deviated septum or to remove nasal polyps

Prevention

You can prevent allergies by working with your healthcare provider to identify substances you are allergic to and potential ways to avoid them. You should also discuss the appropriate use of medications to manage your condition.

Preventing sinus infections involves treating allergies and congestion caused by colds or upper respiratory infections. Infection prevention techniques, such as hand washing and staying away from others who are sick, are also important.

You can help bolster your immune system by getting enough sleep, exercising, eating a healthy diet, and drinking plenty of fluids.

A Word From Verywell

Both allergies and sinus infections can cause significant symptoms that can impair your quality of life. Treatment and relief are available for both, so you should see a healthcare provider if you've had significant symptoms of either condition that have lasted more than two weeks.

Frequently Asked Questions

  • Do allergies cause sinus infections?

    Yes. Untreated allergies can sometimes lead to sinus infections.

  • What is the best OTC medicine for sinus infections?

    Each individual will experience different symptoms and severity of symptoms. However, a nasal decongestant, such as Afrin (oxymetazoline), can help decrease symptoms, inflammation, and open up the nasal passageways to allow better flow of mucus. This medication should not be used longer than three days to avoid rebound congestion. You should check with your healthcare provider or pharmacist before using any new medication.

  • Are sinus infections contagious?

    Some sinus infections are contagious, depending on the underlying cause. If you aren't sure, it's best to avoid other people by staying home from work or school, washing your hands frequently, and covering your mouth and nose when you cough or sneeze.

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6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American College of Allergy, Asthma & Immunology. Allergy facts.

  2. American College of Allergy, Asthma & Immunology. Sinus infection.

  3. Cleveland Clinic. Allergy overview. Updated November 30, 2020.

  4. Cleveland Clinic. Sinus infection (sinusitis). Updated June 4, 2020.

  5. Asthma and Allergy Foundation of America. Allergy diagnosis.

  6. Tufts Medical Center. Are sinus infections contagious?