A person may feel like their seasonal allergies have worsened during and after they have experienced COVID-19. Some research suggests there may be a link between seasonal allergies and long COVID.

Seasonal allergies are allergic reactions to certain pollens. A person with seasonal allergies may experience symptoms including sneezing, coughing, itching in the eyes, nose, or throat, congestion, and fatigue. A doctor may refer to symptoms that affect the nose as allergic rhinitis.

COVID-19 is a disease caused by an infection with the coronavirus, which spreads through small liquid particles from the mouth or nose. It can cause symptoms such as cough, fatigue, fever, and nasal congestion.

This article will cover whether seasonal allergies can worsen after a case of COVID-19 and how viruses and allergies are related.

Coronavirus data

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub for the most recent information on COVID-19.

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It is possible that if a person feels their allergies are worse since having COVID-19, they may still be experiencing symptoms of that infection. The main difference between seasonal allergies and COVID-19 is that COVID-19 can cause symptoms such as a fever, severe fatigue, and a new loss of smell or taste.

COVID-19 is a disease that occurs when a person develops an infection with the coronavirus. It typically infects the upper respiratory tract but can cause symptoms in many places across the body.

Seasonal allergies occur when a person’s body mistakes a harmless substance, such as pollen, as a threat, triggering an immune system response. This response involves the immune system creating antibodies that attack the allergen, causing inflammation. With seasonal allergies, this inflammation may occur in the nose, airways, eyes, or skin.

Although the root cause of both conditions is different, their symptoms can appear very similar. Both conditions can cause:

  • cough
  • difficulty breathing
  • runny nose
  • headache
  • red eyes
  • irritated skin

Learn about the difference between a cold, allergies, and COVID-19.

It may be possible that if a person feels their seasonal allergies are worse after having COVID-19, they could be experiencing symptoms of long-haul COVID-19, also referred to as long COVID.

However, there may be a connection between seasonal allergies and long COVID. Research from 2021 found that many people with long COVID experience heightened mast cell activation, in a very similar way to people with mast cell activation syndrome (MCAS).

Mast cells are part of the immune system. When an allergen is present, they secrete histamines and other chemicals into the blood to fight it off. MCAS describes a condition in which mast cells are overactive in the body, which can lead to frequent and severe allergic reactions.

The paper found similarities between people with long COVID and MCAS and found the severity of symptoms to be the same.

Further research from 2022 noted that COVID-19 could cause disturbances to the immune system, leading to unusual mast cell activation that may cause allergic flare-ups.

Although more research is needed to establish a firm connection between long COVID and seasonal allergies, recent research shows that there may be a possible link involving mast cells.

What is long COVID?

Most people recover from COVID-19 within a few days to a few weeks. For some people, symptoms can carry on longer. A doctor may consider a person to have long COVID, or post-COVID, if they continue to experience symptoms for at least 4 weeks after the onset of the infection.

The World Health Organization estimates that roughly 10–20% of people experience mid- to long-term effects after recovering from COVID-19.

Long COVID can vary in severity and affect multiple organs across the body. Research from 2022 notes that some of the most common long COVID symptoms can be similar to the symptoms of seasonal allergies, with some including:

  • difficulty breathing
  • tiredness
  • headache
  • sneezing
  • dry skin

Learn some possible risk factors for long COVID.

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Allergies occur due to the body mistaking a harmless substance as a threat and following up with an immune system response. The immune system is also involved when the body responds to a virus, which can lead to similar symptoms.

For example, a sinus infection and allergic rhinitis may present similarly. However, allergens trigger the allergic response rather than viruses.

A viral infection can worsen symptoms triggered by allergens. For example, a person with asthma may find that a viral infection, such as the flu, worsens their breathing, which in turn makes it more difficult to manage their allergy-induced asthma.

If a person feels that they are having difficulty recovering from COVID-19, they should see a doctor to discuss the possibility of long COVID and other possible causes of their symptoms. If a person feels their seasonal allergies are worsening and more difficult to manage, a doctor may refer them to an allergist.

The American College of Allergy, Asthma, and Immunology suggests that a person should see an allergist if their allergies are causing:

  • ongoing nasal congestion and sinus infections
  • symptoms for several months of the year
  • symptoms that antihistamines and over-the-counter medications are not managing
  • worsening of their asthma which affects their day-to-day activities
  • symptoms that have an ongoing impact on their quality of life

Learn the best medications for seasonal allergies.

Both the symptoms of COVID-19 and long COVID can look very similar to those of seasonal allergies, so a person may find it difficult to distinguish between them.

Although research into long COVID and allergies is yet to make a concrete connection, early findings suggest that some people may see greater mast cell activation, which may affect allergic reactions.

If a person finds managing their seasonal allergies or COVID-19 recovery challenging, they should see a doctor to find out what treatments can help manage their symptoms.