@cavstat I have allergic asthma, and my experience is that if I control the allergies, I control the asthma and tend to avoid needing to use rescue inhaler medication. I do allergy shots that are specifically made for me by my doctor's office after each individual component is tested for the maximum dose I will tolerate before it causes a reaction, and that is the treating dose in the vial of the extract they make for me. I've also recently been taking generic Zyrtec everyday, but according to my doctor, antihistamines loose their effect if taken repeatedly, so shots are are better control as long as they are current. Avoidance works too by putting on a mask or using a HEPA air filter. Honestly, I don't like giving myself shots, and don't want to do that when I'm overly tired because I have to be concerned about maintaining a sterile injection. Retesting needs to be done every couple years because the shots did work, and lessened the allergy response, so a different dose is needed to be effective. I have to do them about every 4 days to keep shots effective or more frequently if there is a lot of exposure like when molds are very high during damp warm weather. Adding an antihistamine on top of the injection helps. I also have a physical issue with one side of my chest that doesn't always move properly because of muscular tightness related to thoracic outlet syndrome. If I get too much phlegm that gets trapped, because my lungs are not moving enough to clear it, I tend to get a bacterial chest infection and need antibiotics to clear it so thinking about the flu or COVID-19 does make me worry a lot. Recently, I became aware of another issue that was contributing to too much phlegm in my chest and that was from very old root canals in my teeth that failed and were sending infection and cadmium into my jaw bone, and causing inflammation in my body. I made the decision to get Zirconium (ceramic with no metal) dental implants and had my bad teeth removed 4 weeks ago as preparation. Right away, I had a lot less phlegm in my lungs, and my breathing is a lot more relaxed now, and I take fewer breaths per minute now as a norm, and I feel much better. I know that are a lot of factors that affected my breathing and I think that I may have finally broken the pattern I had of having repeated chest infections from trapped phlegm that had been going on for a couple years.
When you have overlapping symptoms, it may be hard to distinguish illness from allergy, and that is so much more important now because of COVID-19. Now that my lung are functioning much better, I am more attuned to any changes in symptoms, and can address it right away, and then if my treatment works, I know that it was allergies at work. The symptoms are slightly different between allergies and viral infection, and there is a good comparison table on this Asthma and Allergy Foundation page that Colleen shared. – Coronavirus (COVID-19): What People With Asthma Need to Know https://community.aafa.org/blog/coronavirus-2019-ncov-flu-what-people-with-asthma-need-to-know
Any inflammation in the body adds up and keeps the immune system busy, so it makes sense to me also that this will distract the immune system from fighting a COVID infection. As for the question about antihistamines, using them has helped me stay well, so I presume that they did not weaken my immune system. Time will tell if I have broken the cycle of bacterial chest infections, and I think everything I'm doing has helped including physical therapy and doing self PT work at home. I have stopped all my PT and non urgent medical appointments because it is too risky to be exposed to others while this pandemic is getting worse on the steep upward curve. Our immune system doesn't know what to do with the Coronavirus, and I have been reading about how it is attaching to receptors in the lungs and heart, and how there are sugar molecules associated with it These receptor sites are also the targets of drugs for management of heart disease and this suggests a need to study the mechanism of how the Coronavirus attaches to and damages heart and lung cells. From what I am reading, it attaches more easily that other viruses. Viruses use cells by injecting their genetic material, and redirecting the host cell to manufacture multiples of the virus which kills the cell, and the new mass of virus is shed from the cell. All of this causes lung damage and may also be happening in hearts as was suggested as a possibility in what I read. The heart speeds up if the lungs don't deliver enough oxygen. Here is a link that explains some of the heart issues with this virus.