The COVID-19 pandemic has brought about numerous health challenges. As research continues, a recognized concern involves the potential development or worsening of allergies following SARS-CoV-2 infection. Many individuals report new allergic symptoms or increased severity of pre-existing ones after recovering from COVID-19. This highlights the virus’s broad impact on the immune system and the need to understand these post-infection changes.
Observed Connections Between COVID-19 and Allergies
Reports from patients and observations within the medical community indicate a connection between COVID-19 infection and the emergence or exacerbation of various allergic conditions. A recent study, published in Nature Communications, found that individuals infected with SARS-CoV-2 showed a 20% higher occurrence of allergic diseases compared to those not infected. The likelihood of developing asthma more than doubled, while the chance of getting allergic rhinitis was 25% higher in the infected group. While some research suggests a link between seasonal allergies and long COVID, a definitive connection between COVID-19 and food allergies or atopic dermatitis has not been consistently observed in all studies.
Individuals with pre-existing allergic conditions, such as asthma or allergic rhinitis, may also face an elevated risk of experiencing long COVID. One meta-analysis of 13 studies, including nearly 10,000 participants, found that pre-existing asthma was associated with an increased risk of long COVID, with an odds ratio of 1.94. Similarly, allergic rhinitis was significantly linked to a higher risk, with an odds ratio of 1.96. These observations suggest that individuals with pre-existing allergies might be more susceptible to prolonged COVID-19 symptoms.
How COVID-19 Might Trigger New Allergies
The mechanisms by which COVID-19 could lead to new or worsened allergies are complex and involve various aspects of immune system dysregulation. SARS-CoV-2 infection can cause widespread inflammation and disrupt the immune system, including its mast cells. Mast cells, found throughout the body, release chemicals like histamine when activated, which can lead to inflammation and allergic reactions. When these mast cells become overactive, they can contribute to conditions like Mast Cell Activation Syndrome (MCAS), which has been observed in some individuals with long COVID.
The virus may also induce an “allergen-like” immune response, potentially contributing to chronic infection or long COVID. This involves a shift from T helper 1 (Th1) to T helper 2 (Th2) cells, which can promote tolerance to the virus and allow its persistence. Studies have identified immune system changes in individuals with long COVID, including altered levels of various immune cells. These immune alterations could contribute to the development or exacerbation of allergies.
Another factor is the observed reactivation of latent viruses, such as Epstein-Barr virus (EBV), in long COVID patients, which can further complicate the immune response and increase susceptibility to allergic reactions. Lower levels of the stress hormone cortisol have also been found in individuals with long COVID. Cortisol plays a role in regulating the immune response, and a deficiency could lead to an overactive immune system, thereby increasing the risk of allergic reactions. These hormonal imbalances, combined with immune dysregulation, may predispose long COVID patients to allergies.
Navigating New Allergy Symptoms
If you suspect new allergy symptoms after a COVID-19 infection, seek medical advice. A healthcare provider can help determine if your symptoms are related to allergies or if they might be lingering effects of COVID-19, as some symptoms like cough, difficulty breathing, runny nose, and headache can overlap. Allergy testing can help identify specific triggers; these tests typically involve skin prick tests or blood tests that measure immunoglobulin E (IgE) antibodies, which are associated with allergic reactions. Blood tests are an alternative if skin conditions or certain medications prevent skin testing.
Once a diagnosis is made, general management strategies can be implemented. Identifying and avoiding triggers is a primary step, which might involve using allergen-proof covers for bedding, regularly washing linens in hot water, and maintaining low humidity to reduce dust mites if environmental allergies are present. For food allergies, an elimination diet can help identify problematic foods, and avoiding these can reduce inflammation. Medications such as antihistamines can help manage common allergy symptoms like sneezing, runny nose, and itching.
For more severe reactions, your doctor may discuss emergency plans, which could include prescribed corticosteroids or an epinephrine auto-injector for anaphylaxis. Maintaining a healthy lifestyle with a balanced diet, regular physical activity, adequate sleep, and stress management techniques can also support your immune system and potentially reduce the risk of developing new allergies. If allergy symptoms are persistent, severe, or not responding to over-the-counter medications, consulting an allergist for specialized care is advisable.