Dear Doctors: I have been dealing with toenail fungus on just a single toe for more than a year. There is a mountain of misinformation about it on the internet, and I keep seeing ads for all sorts of drugstore products that claim they can cure it. Any suggestions for how to deal with this?

Dear Reader: You are asking about a topic that, each time we have written about it in the past, brings a flood of mail. Toenail fungus is a common -- and very stubborn -- infection. Also known as onychomycosis, is estimated to affect between 6 million to 7 million people in the United States. Although the effects are visible on the exposed part of the nail, the fungi that cause the infection are housed within the nail bed. And because our nails are so well-engineered to shield the tips of our toes from potential threats such as moisture and trauma, the fungi that take up residence beneath them are largely protected.

For those who are unfamiliar, symptoms include nails that gradually become discolored, often with a yellowish, brown or gray hue. They also become thickened and malformed, often with a brittle or crumbling texture. As the infection progresses, the nail plate can grow so thick that it becomes difficult to trim. Sometimes the infected area will also exude a musty scent. Once a fungal infection takes hold, the dark and moist environment provided by socks and shoes can help it spread to the neighboring toenails.

When it comes to treatment, the options are somewhat limited. The topical nonprescription ointments and liquids you have been seeing can make the nail look better. However, the protein that makes up the nail plate, which is known as keratin, is not porous. That means topical medications can’t reach the entire site of the infection. Our readers have reported success with home remedies, such as the use of tea tree oil and Vicks VapoRub.

A more effective approach has been an oral antifungal medication, which requires a prescription. The medication enters your blood stream and is delivered to the network of blood vessels that serve the nail bed. As with many medications, antifungals have potential side effects. These include headache and stomach upset. These meds can also affect the liver, which makes liver function tests necessary. The treatment, which lasts several months, is up to 80% effective. It can take from six to 18 months for complete results. And if you stop the medication too soon, the infection can rebound.

More recently, the use of lasers to treat toenail fungus has grown in popularity. This requires multiple treatments and, because data is somewhat limited, the efficacy is not yet clear. An even newer approach, known as cold atmospheric pressure plasma, is now being explored. Also referred to as CAPP, it involves the use of a device that delivers localized shock waves, which researchers say are effective at killing the fungus. This treatment is still being studied and is not yet in use. However, considering the millions of people affected by toenail fungus, it will likely make headlines if and when it becomes available.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: Can you please do a column about familial hypercholesterolemia? It is my diagnosis, and I would like you to explain it. My LDL is over 500. It is my understanding that there are different kinds of LDL. Is that correct? Any information would be helpful.

Dear Reader: Familial hypercholesterolemia, often shortened to FH, is a condition that interferes with the mechanisms the body uses to manage blood cholesterol levels. In medical terminology, “hyper” means that something is above normal, and “emia” refers to the blood. The word “familial” indicates this condition has a genetic component. More specifically, FH results in very high levels of a type of cholesterol known as low-density lipoprotein, or LDL. This puts people living with FH at increased risk of developing heart disease and of having a heart attack at an early age. To understand how and why, we need a few more details.

Cholesterol is a fatty, waxy substance that is transported throughout the body in the blood. The liver produces about 80% of the cholesterol our bodies use, and 20% comes from our diet. Although the focus is often on cholesterol as a risk factor for heart disease, it is needed by every cell in the body. It is a crucial building block of our cell membranes; is essential for the production of certain hormones, including estrogen and testosterone; and is necessary for the manufacture of vitamin D. That said, high levels of cholesterol, particularly of LDL, can lead to a dangerous buildup of fatty deposits within the blood vessels. This significantly increases the risk of narrowing of the arteries.

Cholesterol is classified into two main types. High-density lipoprotein cholesterol, or HDL, helps move lipids from the blood and into the liver for disposal. This has led to HDL being referred to as “good cholesterol.” But low-density lipoprotein does the opposite. It transports lipids from the liver into the blood for delivery to the cells. You are correct that there are different types of LDL. It is broken down into several subclasses, each of which decreases in size and increases in density. It is those characteristics, the smaller size and higher density, that make an overabundance of LDL particularly dangerous. Some researchers have come to suspect that the subclasses of LDL behave differently from one another, and that each may have a unique role in cardiovascular disease.

The good news is that lifestyle choices, along with medical interventions, can have a positive effect on this condition. These include not just changes to diet and the use of medication, but also regular screenings to monitor blood lipid levels. Due to the genetic component, each case of FH is different and benefits from highly personalized treatment. That makes it important for anyone living with FH to seek out expert medical care. Genetic testing can also shed light on the condition and inform treatment choices. It is recommended that, when possible, someone with FH work with a cardiologist who has experience with the disorder.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: I had a COVID-19 vaccine in June 2023, so I’m overdue for another. I’ve heard there’s going to be an updated vaccine coming out in the fall. If possible, I would like to get it at the same time as my flu shot in October. Is the new COVID shot very different from the old one?

Dear Reader: With summer drawing to a close and the autumn months on the horizon, we are easing into the annual trifecta of cold, flu and COVID seasons. Health data show that COVID-19 still surpasses all other infectious respiratory illnesses as a cause of severe illness, hospitalization and, sadly, death. The good news is that the margin by which COVID-19 beats out influenza is the slimmest it has ever been.

More than four years since the start of the COVID-19 pandemic, we have a high degree of population immunity. It is estimated that 98% of people in the U.S. now have at least some degree of protective immunity. This is due, in large part, to the availability of vaccines. Prior infection also plays a role. Another contributing factor in the improved outcomes from COVID-19 infections is the availability of effective treatments, particularly the drug Paxlovid.

You are correct about an updated mRNA COVID-19 vaccine. It was approved by the Food and Drug Administration in August and is now available. The new shots have been adjusted to target the newer variants of the omicron strain, which are driving the most recent surge of infections in the United States. Vaccines protect against infection with the virus. When someone does get COVID-19, being vaccinated reduces the risk of developing severe illness. There is also now evidence that being vaccinated prior to infection cuts the risk of developing long COVID in half.

The fall timing of the updated COVID-19 vaccine is deliberate. It coordinates with the release of this year’s influenza vaccine. As you point out in your letter, this allows people to get both shots at the same time.

The Centers for Disease Control and Prevention continue to recommend the COVID-19 vaccine for anyone age 6 months and older. As in the past, the people at highest risk of severe illness from the virus are adults 65 and older, anyone with a compromised immune system and those with chronic health conditions such as diabetes, heart disease or obesity. Individuals who have not been vaccinated in a year or more, and those who have never been vaccinated, are also at increased risk.

Some people wait to time their vaccines to coincide with the peak months of the respiratory illness season. That is, the colder months that send people indoors, and, thus, into close contact with one another. For those who plan to delay their vaccines, taking additional precautions is recommended. These include avoiding crowds and using a good mask in public places. If you do become ill, seeking medical care may give you access to Paxlovid. And remember to isolate for a few days, which protects the people around you.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)