June 2, 2020 Wei-Shin Lai, M.D.
Allergies are typically caused by trees blooming in the spring. In the summer, we start to see grass allergies and by late summer, the weeds bloom. Fall allergies are caused by various molds and weeds. If you are in a warm area of the country in the winter, you may still have plant-related allergies, but for the most part, winter allergies are indoor, related to pets, mold, and dust (dust mite feces, cockroach feces, etc.). Most people’s allergy symptoms are pretty consistent from year to year. However, sometimes non-drowsy antihistamine medications like Claritin (loratadine), Allegra (fexofenadine), or Zyrtec (cetirizine) lose their effectiveness after a few months. Switching to a different allergy medication can help.
Symptoms of allergies typically include an itchy nose, sneezing, and runny or stuffy nose. The nose is the major problem, and the post nasal drip from a runny or stuffy nose can lead to coughing or a mild sore throat. If someone has asthma, then the asthma may cause shortness of breath. Asthma tends to happen during allergy season because allergens can trigger an asthma attack. I sometimes think of asthma as lung allergies. Some of the processes are similar, like increased mucus production and swelling of the airway. Most people who have asthma also have nasal allergies. In fact, there is an “allergic triad” that describes three conditions that often travel together: allergies (both nasal and food allergies), asthma, and eczema (dry, itchy, red skin). Patients with the allergic triad tend to react poorly to allergens in general.
Here is the list of COVID-19 symptoms and their prevalence. Note that some lucky people never have symptoms at all. Of the people who had symptoms and tested positive, doctors and scientists have compiled a list of common symptoms. I’ve compared these COVID-19 symptoms to allergies.
(% of patients with the symptom)
Possible, sinus headaches
|Shortness of breath||43%|
Possible with asthma
|Loss of smell/taste||30%||Rarely reported|
|Sneezing/itchy nose||? not reported||Frequent|
Allergy comments are based on >10 years of clinical practice. Nasal allergies are so well established, there is no recently published chart with percentages because no one needs the information to characterize the disease anymore.
Starting from the top, coughing is very non-specific. Coughing is the most common symptom of COVID-19, but you can also cough from allergies, especially if you often cough from allergies in the past years. The allergy cough is caused by a post-nasal drip, which is worse as you try to go to sleep because you are leaning back. If the coughing is not worse with positions that would worsen a drip from the back of your nose into your throat, then that may be a bit more concerning. Coughing can also be a sign of asthma. Some asthmatics cough instead of wheeze, and nighttime symptoms are particularly concerning. If you suddenly develop a cough, and you’ve never had allergies that resulted in a cough before, then it may be more than just allergies.
Fever is a defining symptom of COVID-19. Allergies almost never cause a fever, unless it’s gotten so bad that you develop a sinus infection. If you get nasal allergies that badly, then you should be quite familiar with your allergy symptoms already. Currently, if you have a fever, COVID-19 should be ruled out with a coronavirus test. Please note that the chart doesn’t take into account how long it takes you to develop certain symptoms. It only looks at whether or not the symptom occurred at all. Some people don’t develop a fever for a few days or at all. But if you do have a fever, then it’s probably not allergies.
Achiness can be caused by so many things… overdoing it the day before, sleeping funny, or just about anything once you reach a certain age. If it’s accompanied by a fever, chills, or rigors (shaking chills), then you probably have an infection. While there are many possible causes for infections, the current worry is of course, the coronavirus.
Headaches caused by allergies tend to be related to sinuses. Sinus headaches often occur in the area just over your eyebrows or on your cheeks next to your nose. They are usually recognizable as sinus headaches for those who have had them before. Migraine headaches can also occur in people with allergies. Migraines tend to be on one side of the head rather than both, and are often centered just behind an eye, sometimes causing vision abnormalities. Headaches caused by COVID-19 would be related to the fever and general achiness. It would worsen when the fever and achiness worsen, and the location of the headache would resemble a tension headache. Tension headaches can feel like you’re wearing a hat that’s too tight.
The sore throat from allergies and COVID-19 may be hard to distinguish. You’d have to look at the other symptoms.
COVID-19 can be insidious as it causes shortness of breath. You may not even feel short of breath with a very low oxygen level. There have been numerous reports of people obviously walking around with oxygen levels so low they would normally be in an ICU. When you start to have trouble making it up the stairs or to and from the bathroom, you know you are in trouble with COVID-19. The downhill turn can hit pretty fast - within hours. If you have a home pulse oximeter, you should check it and talk to your primary care physician on a phone visit. If you are registering less than 90%, cannot reach a doctor, and feel pretty poorly, you should consider calling urgent care or the emergency room. If your pulse oximeter rates your oxygen level less than 85%, you need to go to the emergency room. If you do not have a pulse oximeter at home, don’t worry about trying to get one. Symptoms are more important than a random number anyway. If you cannot do basic activities like walk across the room to the bathroom to wash your hands, take a shower, go up a flight of stairs, heat and eat a meal, then you need to be hospitalized.
Shortness of breath isn’t a symptom of nasal allergies, but if associated with asthma, it is often accompanied by wheezing or coughing. It is unusual to suddenly develop severe asthma as an adult, so unless you have known asthma, shortness of breath should be assumed to be COVID-19 until it is ruled out. (Shortness of breath is also famously associated with heart attacks, so either way, a trip to the emergency room is in order.)
Gastrointestinal symptoms from COVID-19 are fairly common. Nausea, vomiting, and diarrhea would definitely increase suspicion of COVID-19. Another common symptom is not feeling hungry (anorexia). Some reports lump it in with nausea, but I want to just point it out as a possible symptom because not everyone will interpret anorexia with nausea. (Anorexia in this context is simply not feeling hungry, not the eating disorder.) Allergies don’t normally cause nausea, vomiting, or diarrhea, but allergies can produce so much mucus that some people end up not feeling very hungry.
An interesting symptom of COVID-19 is not being able to smell or taste well. Scientists theorize that the virus attacks the nerves that let us smell or taste. With allergies, smell and taste may be diminished with a stuffy nose. So this is not a good differentiator.
On the other hand, a runny nose is a great differentiator. Allergies often cause a stuffy and runny nose. COVID-19 doesn’t tend to cause a lot of nasal symptoms. While it’s a coronavirus, it’s different from the coronaviruses that cause the common cold. It tends to go straight for the lungs, rather than the nose.
A runny nose, frequent sneezing, and nose itchiness all point to nasal allergies, especially when there is no fever. Other symptoms like headaches and sore throat can overlap both allergies and COVID-19, so you can look at the prevalence of other symptoms to figure out which one you are more likely to have. Of course, it’s also possible to have both. And some people will have symptoms that aren’t conventional for either disease.
I always encourage you to discuss with your medical professional for definitive advice. For people who smoke, vape, or have various pre-existing conditions, the picture can be more complex. The more important disease to rule out would be COVID-19. If you suspect that you may have COVID-19, even though you may not have a bad case, you really should find out for sure with a PCR (nose swab) test. It’s important to be in “the system” so your contacts can be properly traced and notified. You would also receive coaching to stay home and self-isolate. A public health official would help to make sure that you have everything you need to properly self-isolate - including accurate information and even food delivery.
We will likely go through at least another four seasons with this virus. While we wait for the coronavirus vaccine, we have to prepare for the possibility of accidentally catching COVID-19. Various allergies throughout the year can complicate our socially-distanced lives and give us a bit of a scare. While not perfect, recognizing the few symptoms where the coronavirus differs from allergies can tell us when to visit the doctor and when to take a Claritin.
Brought to you by AcousticSheep LLC, maker of SleepPhones®, the most comfortable headphones you can wear in bed. SleepPhones® were invented by the author and her husband. Click here for more information. Dr. Lai also blogs about the coronavirus, having almost joined the CDC 15 years ago. 2020 © AcousticSheep LLC