COVID-19 vs. Allergies: Do I have allergies or COVID-19?

Is sneezing a symptom of COVID-19 or allergies?

If you are feeling sneezy, feverish, short of breath, exhausted, or achy, you may be wondering if your signs and symptoms are due to seasonal allergies or COVID-19. The table below covers many of the signs and symptoms of COVID-19 and allergies. However, there are other features that help to identify the two conditions. The following will help to further identify the similarities and differences between these conditions.

An allergy develops due to hypersensitivity of the body's immune system response to a usually harmless substance in the environment. Such substances (known as allergens) may be

• foods,
• chemicals like perfumes,
• plants,
• animal dander, and
• many others.

For the patient, one or more substances exposed to mucus membranes or skin may trigger an allergic reaction (for example, an asthma attack, skin rash, and symptoms listed in the table above). In contrast, COVID-19 is a disease caused by the virus SARS-CoV-2. Allergies are not contagious, but COVID-19 is very contagious. Rarely does an allergy cause life-threatening problems (except for an acute severe asthma attack), while about 20% of COVID-19 infections can require hospital care. Pneumonia usually does not occur with allergies but people with rather severe SARS-CoV-2 infections often develop pneumonia. Some allergies occur seasonally (pollen production, "allergy season"). Seasonality is not yet evident with COVID-19 due to a lack of data.

COVID-19 is a viral (SARS-CoV-2 is the name of the virus) respiratory disease identified in December 2019. In contrast, allergies have multiple triggers, are not contagious, and have been identified in humans for many generations. COVID-19 has an incubation period of about 2-14 days, while allergy symptoms don't have an incubation period. Person-to-person transmission spreads the viral disease. Allergies are unique to each individual and do not spread to other people.

COVID-19 progresses over a few days with increasing severity of signs and symptoms in people who have symptoms, while people with allergies usually have signs and symptoms in minutes to hours after exposure to a trigger substance. Both COVID-19 and allergies, when severe, may need emergency respiratory support and other supportive care. This need can arise quickly in some people. One difference between COVID-19 and severe allergic reactions (anaphylaxis, for example) is that severe COVID-19-infected patients usually have had bouts of high fever and chills before respiratory failure. Also, there are rapid tests (5-15 minutes) that can identify those people infected with SARS-CoV-2 virus. Tests for allergies to determine the triggers may take a number of tests over time.

However, the Centers for Disease Control and Prevention (CDC) officially list the following as symptoms that may appear 2-14 days after exposure:

• Cough
• Shortness of breath or difficulty breathing and at least two of the following
  • Fever
  • Chills
  • Repeated shaking with chills
  • Muscle pain
  • Headache
  • Sore throat
  • New loss of taste (ageusia) or smell (anosmia)

The CDC suggest people who have the following seek medical attention immediately:

• Difficulty breathing
• Persistent pain or pressure in the chest
• New confusion or inability to arouse
• Bluish lips or face

However, other signs and symptoms not yet listed by the CDC but may be signs of COVID-19 infection include COVID toes (reddish-purple discoloration of skin on the toes) and stroke in some patients (<50 years of age due to unusual thrombus formations) as an initial sign of COVID-19 infection. Some children may exhibit signs and symptoms of Kawasaki disease (fever, rash, eye irritation, and swollen lymph nodes with possible cardiac problems) as an indication of COVID-19 infection.

Over time, as the CDC and other researchers investigate COVID-19 infections, they may notice other features of the disease (for example, higher infection rates in males and African-Americans, and possible severity reduction and/or infection rate in people who in the past have had a BCG vaccination) and possibly expand the list of potential associated signs and symptoms.

Treatments for signs and symptoms that may accompany both allergies and COVID-19 (conjunctivitis, sinusitis, congestion, and others) are mainly over-the-counter (OTC) medications. Your doctor may treat other problems that may occur at the same time (like ear congestion/infection, bronchitis, and sinus infection) with antibiotics.

The U.S. Centers for Disease Control and Prevention (CDC) recommends that people with prescribed allergy medication follow their doctor's recommendations and continue immunotherapy. Other treatments may include immunotherapies such as allergy injections and/or removal of nasal polyps. None of these treatments treat COVID-19.

Treatment of COVID-19 currently (Apr. 30, 2020) is supportive care with severe infections requiring oxygen delivery and/or respiratory support with a ventilator. COVID-19 severe infections are due usually to viral pneumonia, which is not responsive to epinephrine. Although there is no definitive treatment, vaccines, antiviral drugs, convalescent serum (immunoglobulin), and immune enhancement methods are under active investigation as potential treatments. In late April, an antiviral drug, remdesivir, showed a significant reduction in hospitalization days for COVID-19 infections. It is the first drug to show some ability to help patients.