Dear Doctor: I have a question I’m sure is on the minds of others, as well -- where is the flu this year? All we are hearing about is COVID-19. Did the flu vaccine they gave work that well? Is no one getting the flu anymore?

Dear Reader: You’ve asked an excellent question with a somewhat complex answer. The short version is that, yes, incidence of influenza infection has been markedly lower for the flu season thus far. We’re seeing that in our own practices. As of the middle of February, we have not had a single case of influenza. To say that’s unusual is an understatement.

Our experience is reflected in the numbers that the Centers for Disease Control and Prevention use to track the course of influenza infection in the United States. In the last week of 2020, for example, only 1% of samples tested positive for influenza. Typical results at that time of year are in the 20% to 30% range. Global tracking data also mirror this trend.

A number of factors are playing a role in this year’s surprising flu season numbers. An important one is the many mitigation measures we’re all taking in the fight against COVID-19. These include social distancing, wearing a mask, vigilant hand-washing and cleaning high-touch surfaces. Environments that act as natural petri dishes for the spread of respiratory infections, such as offices and classrooms, are either severely restricted or completely shut down. Ditto for group activities such as concerts, sporting events, travel, dining, bars and other recreational activities. In physically protecting ourselves and limiting our potential exposure to the airborne coronavirus, we’re also shielding ourselves from the coughs and sneezes and surface contamination that spread the flu. The influenza virus, less transmissible than the coronavirus, is proving no match for these multiple layers of precautions.

The differences in tracking methods for COVID-19 and the flu are playing a role. With the coronavirus, the goal is to count every possible case in order to understand the trajectory of the pandemic. To that end, many millions of coronavirus tests have been administered, and all of the resulting data collected and logged. Statistics about the number of cases each flu season, by contrast, are estimates. These are arrived at by analyzing testing data collected from designated public health and clinical laboratories, and from a network of medical practices and hospitals.

It’s also important to note that people aren’t visiting the doctor as much as in pre-pandemic days. When they do seek medical care, the respiratory illness they’re most concerned with is COVID-19, so that’s the test they’re most interested in getting. There’s evidence that a number of people are opting to treat suspected flu-related illnesses at home, which also lowers the reported influenza numbers. However, influenza-related hospitalization rates, with just 155 lab-confirmed admissions from Oct. 1, 2020, to Jan. 30, 2021, bolster the idea that this year’s flu season is unusually mild.

If mask-wearing and other physical precautions continue after the epidemic, then we may continue to see lower influenza rates in the future.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I’m 27 years old and have itchy skin that my doctor says is psoriasis. It’s not all the time -- it comes and goes. Sometimes it’s bad, and other times it’s not that noticeable. I’ve heard that what you eat matters. Can my diet help prevent or control the condition?

Dear Reader: Psoriasis is a chronic skin condition associated with a malfunction of the immune system. It is marked by the overproduction of skin cells, which results in raised areas of dry, reddened and flaking skin. These areas of inflammation, which are sometimes topped by silvery scales, most often appear on the elbows, knees and scalp. However, they can occur anywhere on the body. Additional symptoms can include burning, soreness and itching; nails that grow thicker than normal or develop pits or ridges; and stiffness or swelling in the joints. Susceptibility to psoriasis, which occurs in both women and men, is inherited. The condition is much more common in adults than in children.

The reasons that the immune system goes a bit haywire aren’t yet fully understood. However, flares are associated with triggers such as physical or emotional stress, cold weather, the use of tobacco products and skin injuries. And you are correct that some studies have found that diet may also play a role.

Research suggests that avoiding inflammatory foods may help ease some psoriasis symptoms and lessen the frequency of flares. Chief among the culprits is sugar, which has long been linked to inflammation. In a mouse study published last year in the Journal of Investigative Dermatology, researchers were able to trigger inflammatory changes in the skin in just a few weeks on a high-sugar diet. Other foods that have been linked to inflammation include alcohol, red meat, saturated fats and the highly refined carbohydrates found in snack foods and ultra-processed foods.

What you do eat can be just as important. Some studies have found that the so-called Mediterranean diet, with its focus on fish, seafood and olive oil, as well as a wide range of fresh vegetables, fruit and leafy greens, may also improve symptoms. These fish-forward diets are rich in n-3 polyunsaturated fatty acids, which are also known as omega-3 fatty acids. These types of fats appear to have an influence on something known as eicosanoids, which are molecules that play a role in causing inflammation. With an increase of omega-3 fatty acids in the diet, researchers suspect that inflammatory processes may be suppressed.

Diet alone has not been found to either control or cure psoriasis, so it’s important that you follow the treatment plan outlined by your doctor. And when it comes to food, the responses to dietary changes in people living with psoriasis are highly individual. Some patients have found that a vegetarian diet can lessen the severity of their condition. Others have reported an increased sensitivity to gluten. Pay attention to what you eat, and note whether or not it appears to consistently correspond to changes in your level of inflammation. You may uncover some personal dietary triggers that can help you in managing your condition.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I am a 72-year-old man and have been diagnosed with aortic regurgitation. My cardiologist said since I’m not experiencing any of the usual symptoms connected with this, he thinks I should just continue to monitor it until I do. What can I expect if and when I do start experiencing symptoms?

Dear Reader: Aortic regurgitation is a condition in which the aortic valve in the heart isn’t closing properly. The aortic valve separates the left ventricle, which is the lower pumping chamber of the heart, from the aorta. When functioning properly, it’s a one-way valve that closes completely between heartbeats. As with the other three cardiac valves, the main job of the aortic valve is to maintain the one-way flow of blood through the heart.

When someone has aortic regurgitation, the valve isn’t closing tightly. This allows a portion of the oxygen-rich blood, which the left ventricle had just pushed into the aorta during a heartbeat, to flow back into the chamber as the ventricle relaxes. The leakage interferes with optimal blood flow through the heart and throughout the body.

As a result of inadequate blood flow, which delivers oxygen to the tissues of the body, people with aortic regurgitation can become easily fatigued and out of breath. In order to compensate for the glitch in the system, the heart will begin to work harder. Over time, this can cause the left ventricle to become enlarged. It can also cause a condition known as hypertrophy, which is when the walls of the ventricles thicken due to the extra work they’re being asked to do. These structural changes make the left ventricle less efficient and add to the burden on the heart.

Aortic regurgitation is often symptom-free when it is mild. It is typically detected when a physician listens to the heart and hears the tell-tale sounds of a leaky valve. As the condition begins to worsen, symptoms can include the fatigue and shortness of breath that we mentioned, as well as chest pain, irregular heartbeat, swelling in the feet and ankles and difficulty breathing when lying down. These are what your physician will be looking for. In more severe cases, diastolic blood pressure -- that’s the bottom number -- becomes low and is often accompanied by a forceful heartbeat, known as a “bounding” pulse. Some people may experience severe light-headedness that can lead to fainting.

The decision to monitor your condition without a surgical intervention at this time is known as watchful waiting. In making that choice, a cardiologist weighs a number of factors. These include the severity of the individual’s condition, the appearance of their heart as obtained through scans, and the person’s general health. When someone does need surgery to repair or replace an aortic valve, it can often be done via a catheter that is threaded through a vein. Although this is a minimally invasive procedure, it’s still surgery and, therefore, carries some risks.

If you begin experience any of the more advanced symptoms that we have discussed, it’s important to seek out immediate medical care.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)