Omicron Symptoms vs. Allergies: How to Tell the Difference

Millions of people experience symptoms like sneezing, headache, fatigue, and coughing each year, whether from seasonal allergies or viral infections like COVID-191 . The Omicron variant of SARS-CoV-2, in particular, causes symptoms that often overlap with allergies, making it challenging to distinguish between the two2 . Understanding the subtle differences and key factors can help individuals identify their condition and seek appropriate care3 .

Omicron and Allergy Symptoms Compared

Both Omicron COVID-19 infection and allergic rhinitis share several respiratory symptoms, including nasal congestion, runny nose, sneezing, sore throat, headache, and fatigue2 4. The Omicron variant tends to cause more upper respiratory symptoms such as nasal congestion and runny nose compared to earlier COVID-19 strains5 . Allergies, on the other hand, are immune system responses triggered by airborne allergens like pollen, dust mites, or molds, rather than viral infections6 3.

However, beyond these overlapping symptoms, the two conditions diverge in important ways. Fever and muscle aches are common in COVID-19 infections but are rare or absent in allergic rhinitis7 8. Fever is a physiological response that helps the body fight infection by inhibiting pathogen replication, and it is considered a hallmark symptom of COVID-198 . Allergic reactions do not typically cause systemic malaise or fever8 .

Loss of smell (anosmia) and taste (ageusia) are more characteristic of COVID-19 infections. Sudden anosmia is a strong indicator of COVID-19 and is less common in allergies, where any smell loss is usually mild and related to nasal congestion8 . Allergic rhinitis may cause mild hyposmia (reduced smell) due to nasal obstruction but not the sudden, severe loss seen in COVID-198 . Itchy and watery eyes are typical of allergies but uncommon in COVID-198 9.

💡 Did You Know?
Both Omicron and allergies share symptoms of sneezing, headache, fatigue, and coughing, which can cause confusion1 .

Key Factors for Distinguishing Illnesses

Allergy History

A detailed clinical history is essential in differentiating allergies from COVID-19. Allergic rhinitis symptoms tend to recur predictably during pollen seasons or specific allergen exposures, often with a history of similar symptoms in previous years8 7. Patients with allergies usually recognize their triggers and symptom patterns3 . In contrast, new onset of respiratory symptoms without a history of allergies suggests an infectious cause like COVID-197 8.

• Allergic symptoms often occur seasonally or with specific allergen exposures7 .
• Recurrent seasonal or exposure-related symptoms are typical in allergic rhinitis8 .
• Absence of prior allergy history favors infection as the cause of new symptoms7 .
• Allergies usually do not cause shortness of breath unless asthma is present3 .
• Sudden onset of symptoms, especially outside allergy seasons, raises suspicion for COVID-1910 .

Unhelpful Allergy Medications

Response to allergy medications can help distinguish allergic rhinitis from COVID-19. Antihistamines and nasal steroids effectively relieve nasal congestion, runny nose, and sneezing caused by allergies8 . However, these medications do not alleviate systemic symptoms such as fever, muscle aches, or loss of taste and smell seen in COVID-197 8.

• Allergy treatments relieve nasal symptoms but do not affect systemic symptoms seen in COVID-198 .
• Nasal steroids and antihistamines are effective for allergic rhinitis symptoms8 .
• Allergy medications do not improve COVID-19-specific symptoms like anosmia or dyspnea7 .
• Lack of symptom improvement with allergy medications may indicate infection7 .
• Patients with allergies often notice symptom relief after medication, unlike those with COVID-193 .

COVID-19 Testing

“Any severe symptoms like shortness of breath or difficulty breathing warrant seeking medical care.”

— Scott Feldman, MD, PhD, Perelman School of Medicine, University of Pennsylvania3

Because symptoms of Omicron COVID-19 and allergies overlap significantly, testing remains the definitive method to distinguish between the two conditions7 8. Rapid antigen or PCR tests for SARS-CoV-2 are essential when new symptoms arise, especially if fever, sudden loss of smell, or systemic symptoms are present10 .

• Testing is critical for accurate diagnosis when symptoms overlap7 .
• Rapid COVID-19 tests can confirm or rule out infection8 .
• Testing is advised for sudden onset of new symptoms or fever10 .
• Patients with known allergies but new fever or worsening symptoms should test for COVID-193 .
• Severe symptoms like shortness of breath require immediate medical attention regardless of cause3 .