Why are COVID-19 symptoms changing?

Q: Every time I turn on the news and hear about the coronavirus, the symptoms keep changing. Why is that? How do we even know when we should go see a doctor?

A: It feels like it's been forever, but news of the virus that causes the disease we now know as COVID-19 first emerged in the U.S. at the start of 2020. (The name is shorthand for "coronavirus disease 2019.") It's caused by a novel - never seen before - coronavirus, which is the same type of virus that causes upper respiratory infections, including the common cold. This particular virus is new to humans, which means that not only do we lack immunity, but also that we're learning about its symptoms and effects in real time.

Our first glimmers of understanding came from patients infected in the initial outbreaks. At that time - and it still is true today - common symptoms included a new cough, fever and shortness of breath. The severity of the resulting illness ranges from something akin to a mild cold to the devastating pneumonia that has taken so many lives throughout the world.

As the number of infections continues to grow, so does the data set used by the medical and scientific communities to understand the virus's effects and behavior. We learned that older adults and those with underlying health conditions are at greatest risk of becoming gravely ill. Children appear to be somewhat safe from the virus. And as screening got underway, it has emerged that some people who never exhibited any symptoms at all have tested positive.

Now, close to five months into what has become a global pandemic, additional symptoms and effects of COVID-19 continue to emerge. One, noted anecdotally by people who shared their stories after becoming ill, is a sudden loss of the sense of smell. Known as anosmia, it's believed to occur in anywhere from one-fifth to one-half of all cases. A study in Europe pegged the prevalence of anosmia in COVID-19 patients at more that 85%.

Additional reported symptoms include chills, muscle pain, aching joints, sore throat and persistent headache. The disease is known to cause gastrointestinal symptoms that include nausea, vomiting or diarrhea. In addition to anosmia, neurological symptoms can include tingling or numbness in the extremities, muscle weakness, dizziness, confusion and delirium. Although seizures, stroke and abnormalities in blood clotting have been reported, these symptoms appear to be rare.

An effect of the virus, which is widely reported but is not yet part of the Centers for Disease Control and Prevention's list of symptoms, is extreme fatigue.

Some children and a few adults have experienced something dubbed "COVID toes," which is a red or purple rash similar to frostbite or chilblains.

All of this has prompted the CDC to continually update information pertaining to COVID-19 on its website. The amended guidelines about when to seek emergency medical care now include trouble breathing, persistent pain or pressure in the chest, bluish lips or around the face and the onset of confusion. For more information, visit the CDC website at cdc.gov. Links to a variety of information are on the front page.

Q: I'm 102 years old and a World War II veteran. My problem is I pass a lot of gas. Several days ago, I had an apple and a small piece of sweet potato, and I stunk up the whole house. I had to open all of the windows and doors. Do you have any suggestions?

A: We do have some thoughts on your issue, but first we want to congratulate you on a long life. Our readers often include their age in their letters, and you have surpassed them all by several years.

Internal gas is a fact of life. Whether it's emitted through the mouth as a burp or through the anus as flatulence, it's actually a sign the body is functioning properly. Gas can accumulate as a result of air ingested while eating, drinking, speaking or swallowing. It's also a byproduct of digestion, during which gut bacteria help break down food and emit a range of gases as they work. Most flatulence is made up of carbon dioxide, methane and hydrogen, which are essentially odorless. A small percentage of passed gas includes hydrogen sulfide, which has a powerful odor. Believe it or not, we humans pass gas from one dozen to two dozen times per day.

When excessive gas is accompanied by additional symptoms such as bloating, abdominal pain, loose stool or diarrhea, poor appetite, nausea and unexplained weight loss, it can signify the presence of underlying intestinal issues. These can include irritable bowel syndrome, inflammatory bowel disease, celiac disease, Crohn's disease or small-intestinal bacterial overgrowth. If you do have these additional symptoms, be sure to let your doctor know.

Another factor in excessive gas is a person's age. Due to ongoing changes in our bodies as we grow older, our digestive systems become less efficient at processing food we eat. Some people may even develop lactose or fructose intolerance.

One approach to the problem is to identify the specific food triggers. You can do this by eliminating all suspected foods from your diet, then gradually reintroducing them one by one. Common culprits include high-fiber foods, certain fruits, cruciferous vegetables, beans and items with the artificial sweetener sorbitol. Keep track of symptoms, and you'll be able to identify not only the specific foods that lead to excess gas, but also the serving size at which it becomes a problem.

You have several options to manage flatulence. Some people swear by probiotic foods and supplements, which can balance the gut. Your health care provider can help you decide if this is an option for you and advise you on specifics. Over-the-counter anti-gas preparations, such as Beano, or those that contain simethicone (Mylanta II, Maalox II) or bismuth (Pepto-Bismol) can reduce gas. Taking Lactaid, an enzyme supplement, helps people who have trouble with milk products.

And take a look at your prescription medications. Blood pressure drugs, narcotics and allergy meds can slow digestion and are associated with excess gas. Always check with your doctor before making any changes to medications.

• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.