Allergies vs Sinus Infection: How to Tell the Difference

By Zina Semenovskaya, MD
Medically reviewed checkmarkMedically reviewed
September 9, 2022

Allergies and sinus infections can have similar symptoms, but there are ways to tell them apart. To help you better self-diagnose and decide what type of treatment may be best, in this article, I’ll explain the differences between allergies and a sinus infection.

First I’ll discuss the symptoms, causes, and timing of each, as well as how healthcare providers diagnose allergies and sinus infections. Then I’ll cover ways to treat each and when to see a healthcare provider about your symptoms.

Common Symptoms

As you’ll see below, there is some overlap of symptoms of allergies vs sinus infection.

However, sinus infections tend to cause more severe symptoms.

Allergies

Sinus infection

  • Nasal congestion
  • Headache
  • Difficulty breathing through the nose
  • Sinus pressure around the cheeks and eyes
  • Yellow or green mucus
  • Unproductive nose blowing
  • Tooth pain
  • Bad breath
  • Fever

Key differences

The main difference between allergies vs sinus infection is that allergies are an ongoing problem that can come and go as you are exposed to triggers.

For example, they may occur seasonally, when pollen and other allergy triggers are the worst. Symptoms may also come on suddenly, such as feeling congested or itchy shortly after breathing in an allergen. 

On the other hand, since sinus infection symptoms may come on more gradually and be persistent.

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Causes

Different things cause allergies and sinus infections.

Allergies

Allergy reactions are driven by an immune response to what you are allergic to. When you come into contact with the allergen, your body releases histamines, a natural chemical that triggers the typical allergy symptoms.

Sinus infection

Sinus infections are typically caused by viral infections but can be caused by bacterial infections. Sinus infections may also be caused by allergies if there is chronic inflammation and irritation in the nasal passages.

In particular, severe, untreated allergies can predispose a person to viral or bacterial sinus infections.

How Contagious Are They?

Allergies are not contagious. However, the causes of some sinus infections, such as viral or bacterial infections, can be extremely contagious.

Sinus infections that develop as a result of severe allergies or blocked nasal passages are not contagious to others.

Timing

Symptoms from allergies and sinus infections set in at different times. The duration of each also differs because they have different causes.

Allergies

  • Symptom onset: Can happen within minutes after exposure to triggers such as pollen, mold, and dust. Symptoms can also wax and wane over several months if there is an ongoing severe allergen exposure, such as to pollen.
  • Symptom relief: Can clear within hours after removal from exposure, or may be constant during high allergy seasons. Allergy medications, like antihistamines, may provide partial or complete relief.

Sinus infection

  • Symptom onset: If caused by a virus or bacteria, the incubation period is typically 1-3 days. You may notice the symptoms develop gradually and then worsen and are persistent if not treated.
  • Symptom relief: Sinus infections caused by viral infections typically resolve on their own within 1-2 weeks. In some cases, viral sinus infections can lead to bacterial sinus infections if bacteria gets trapped in the nasal passages. Bacterial sinus infections typically require antibiotics. Sinus infections caused by ongoing inflammation and irritation from allergies may seem to never clear up on their own.

Diagnosis

A medical provider can determine if you have allergies vs sinus infection.

Allergies

Medical providers typically use skin tests or blood tests to diagnose allergies. Once they identify your allergens, they can recommend treatments and lifestyle changes to manage your disease. In many cases, you may be allergic to more than one thing.

Sinus infection

To diagnose a sinus infection, a medical provider may ask about your symptoms and perform a physical examination, specifically pressing on your sinuses and nearby areas. 

In more severe cases and when symptoms are persistent, a CT scan may be performed to identify potential blockages or other contributing factors.

Treating Allergies

Depending on the symptoms, allergies can be treated with home remedies or over-the-counter (OTC) or prescription medications.

Home remedies

The following natural remedies may provide symptom relief for allergies:

  • Rinsing the sinus cavity with a neti pot or saline spray
  • Using HEPA air filters
  • Using a humidifier
  • Reducing exposure to allergens

Medications

Many allergy medications are available:

  • Over-the-counter allergy medications: Some allergy medications are meant to be taken daily. These include loratadine (Claritin), cetirizine (Zyrtec), and levocetirizine (Xyzal). Other allergy medications, like diphenhydramine (Benadryl), are intended for as-needed use. People generally find that one allergy medication is more effective than another, so see which works best for you.
  • Prescription allergy medications: When OTC medications do not work, medical providers may prescribe allergy treatments. These can include corticosteroids, mast cell stabilizers, decongestants, and nasal sprays.

Talk to a healthcare provider before taking OTC allergy medication. These can interact with other medications and supplements and can cause complications if you have other health conditions.

Decongestants and antihistamines especially may be problematic for people with liver problems, kidney problems, or high blood pressure.

Treating a Sinus Infection

Most sinus infections caused by viruses or allergies will clear up on their own, although home remedies or medications may help ease symptoms.

Bacterial sinus infections need antibiotics.

Home remedies

If you have a sinus infection, the home remedies below may help address symptoms and discomfort:

  • Rest
  • Staying hydrated
  • Saline spray
  • A neti pot
  • Warm compresses on the cheeks or nasal passages
  • Steam inhalation from a bowl or shower

Medications

Some OTC medications can help alleviate sinus infection symptoms and discomfort.

Always use as directed to avoid further complications.

  • OTC pain relievers like acetaminophen (Tylenol) or ibuprofen (Advil) may help alleviate head pressure
  • OTC antihistamines, such as diphenhydramine (Benadryl), may help with congestion
  • Decongestant nasal sprays like oxymetazoline (Afrin) or fluticasone (Flonase) may help decrease nasal inflammation and congestion
  • Expectorant medications such as guaifenesin (Robitussin, Mucinex) may reduce congestion and help clear mucus
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When to See a Doctor

If your allergy symptoms are extreme or seem to worsen, you may need testing to determine your allergens and prescription medication for relief.

Sinus infections usually resolve on their own, but if home remedies and OTC medications don’t help with your symptoms or if the infection persists, see a medical provider. They can make an accurate diagnosis and recommend effective treatments.

Also see a medical provider if any of the following occur:

  • You are sick for more than 10 days without improvement or with symptoms that worsen
  • You have severe headaches that do not get better with OTC pain medication
  • You have a fever of 100.4ºF or higher for more than three days
  • You have vision problems or changes
  • You get frequent sinus infections
  • You have red or pink nasal discharge or mucus
  • You experience ringing in your ears or other hearing problems
  • You have severe dizziness, difficulty walking, or you pass out

How K Health Can Help

Did you know you can access online urgent care with K Health?

Check your symptoms, explore conditions and treatments, and if needed, text with a healthcare provider in minutes. 

K Health’s AI-powered app is HIPAA compliant and is based on 20 years of clinical data.

Frequently Asked Questions

How do you know if you have allergies or sinus infection?
Nasal congestion, headaches, and problems breathing through the nose can be caused by both allergies and a sinus infection. If you were recently exposed to an allergen and have itching, a rash, or sneezing, it may be allergies. However, if you notice yellow or green mucus, fever, tooth pain, or blocked nasal passages, you may have a sinus infection. A medical provider can determine which of these two conditions you have and recommend treatment to ease symptoms.
Can allergies feel like a sinus infection?
Yes, allergies and sinus infections have some overlapping symptoms. In some cases, allergies can cause sinus infections.
Can seasonal allergies cause a sinus infection?
Yes, inflammation from irritated nasal passages can lead to viral and bacterial sinus infections.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.

Zina Semenovskaya, MD

Dr. Semenovskaya specializes in emergency medicine, and received her medical degree from Weill Cornell Medical College. She is currently the medical director at Remote Emergency Medicine Consulting, LLC and splits her time working clinically as an emergency medicine attending in California and Alaska. She is the first of our doctors to be fluent in Russian.

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