Hello, dear readers, and welcome to the first column of high summer. You’ve kept our inbox full, so we’ll dive right in.

-- A recent column about vitamin D prompted a reader to ask this follow-up question: “It is my understanding -- via a doctor -- that when you reach 65 to 70, the body’s ability to make vitamin D begins to decrease. Is this true?”

Yes, the doctor you spoke to is correct. As we age, we experience a decrease in the ability to synthesize vitamin D. This, along with less time in the sun, and a drop in dietary intake, can lead to deficiency. Since this vitamin plays a role in both physical and mental well-being, it’s important to monitor vitamin D levels in the elderly. This can be done via a blood test, and if a deficiency is found, it can be addressed through diet and supplements.

-- We’ve fielded a few questions about air fryers, which are the countertop appliance of the moment. They cook using a fan that circulates super-heated air and, with just a tablespoon or so of oil, crisp food in the same (well, similar) way that deep-frying does. A reader from Tulsa, Oklahoma, wondered whether this sounds too good to be true and asks, “Are there any negatives to eating foods that have been cooked in an air fryer?"

The good news for air fryer fans is that foods cooked in this manner can be up to 70% lower in calories than those cooked via traditional deep-frying. The devices may also decrease the presence of potentially dangerous compounds like acrylamide, which are created during the deep-frying process. However, high-heat cooking of any kind has been associated with the formation of other potentially dangerous compounds. And remember, air-fried foods are only as healthy as the ingredients you’re starting with.

-- Our column about an elderly man wanting to get a dog continues to get a lot of thoughtful replies, such as this one from a reader in Fresno, California: “You left out two important things -- assessing the elderly person's physical, mental and financial capabilities, and the major differences in the care needed by different breeds. A mature dog with no major physical or emotional problems and that does not need much grooming or running is a very different commitment than a puppy.”

-- We recently wrote about advance directives for dementia, in which an individual describes the medical interventions that he or she doesn’t want as the condition progresses. A reader in Terre Haute, Indiana, adds that it’s important to make sure that these directives are accompanied by the specific legal documents required by the laws of their particular state.

We thank you, as always, for your interest in this column. Just a reminder -- we can’t answer specific questions about medications, make a diagnosis or offer a second opinion. Also, space limitations mean that sometimes answers aren’t as in-depth as some readers would like. We’ve noticed that our readers aren’t shy about adding to, arguing with or correcting our work, and we are always happy to revisit previous topics here in our monthly conversations.

(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: We moved from the city to rural Massachusetts, and suddenly Lyme disease is a real threat. I’ve read about it forever, but now that we’re here, I realize I don’t know much about the disease. How do you know if you’ve got it? And how do we protect ourselves and our kids?

Dear Reader: Lyme disease is one of a range of illnesses that can occur when an individual is bitten by a tick. In the case of Lyme disease, the tick has been infected by a bacterium known as Borrelia burgdorferi. In the eastern half of the United States, the bacterium is carried by the blacklegged tick, also known as the deer tick. On the Pacific coast, the disease is spread by the western blacklegged tick.

In order to transmit the disease, the tick must have been attached to its host for at least 24 hours. But because these ticks are quite small -- they range in size from a poppy seed to a sesame seed, depending on the stage of their life cycle -- they can be easy to miss. About 30,000 cases of Lyme disease get reported to the Centers for Disease Control and Prevention each year, but epidemiologists estimate that the true number is closer to 300,000.

One of the challenges of Lyme disease is that the symptoms, which vary depending on the stage of infection, are similar to indicators of other common conditions. In its early stages, Lyme disease can cause fever, swollen lymph nodes, chills and body aches, which are also symptoms of upper respiratory viral infections. Another early symptom can be a localized skin rash, which sometimes clears at the center as the edges expand, forming a distinctive target shape. However, this rash has been found to be a symptom in only about 70% of Lyme cases. To add to the uncertainty, the rash doesn’t always follow the target-shaped pattern. Stiffness and joint swelling, which can arise days or months after the tick bite, mimic arthritis.

Additional symptoms that can arise days or months after an infection include pain in the joints and tendons, heart arrhythmias, dizziness, nerve pain, shortness of breath, loss of muscle tone on one side of the face and even changes to memory and cognition. Anyone with these symptoms who has been bitten by a tick, or who lives in tick country, should seek medical attention. Diagnosis includes a history of potential tick exposure, and it may include lab tests to detect antibodies to the bacterium. Treatment of early-stage Lyme disease with antibiotics such as doxycycline, amoxicillin or cefuroxime is usually quite effective.

Ticks are found in wooded and brushy areas, lawns and gardens, and on outdoor pets. Protect yourself with light-colored clothing, which makes ticks easier to see. Clothes and gear can be treated with the insecticide permethrin. Tuck pants into socks and remember protection for your head. Always perform whole-body tick checks after outdoor activities. If bitten, remove the tick with fine-tipped tweezers, grasping as close to skin as possible. Clean area thoroughly, and see if your physician wants you to save the tick. If so, wrap it in tape. And remember -- a tick bite doesn’t automatically equal Lyme disease.

(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: Like a lot of older people, I suffer from hemorrhoids that cause some pain as well as intermittent bleeding after bowel movements. My doctor recommended surgery, but I’ve also found relief using a hemorrhoid cream. What’s the best treatment?

Dear Reader: "Hemorrhoids" is the name given to a common condition in which veins in the tissues of the lower anus or the rectum become inflamed and swollen. They can be internal or external, and each type causes different symptoms.

Internal hemorrhoids occur within the rectum, which is the lowest portion of the colon, or large intestine. Although these can sometimes cause bleeding, they tend to be painless. External hemorrhoids present as visible bumps or swellings on and around the skin of the anus, which is the opening through which feces passes. External hemorrhoids often cause pain and intense itching around the anus, and they can bleed.

Both types of hemorrhoids can become thrombosed, which means that a blood clot has formed inside. Internal hemorrhoids can also prolapse, which means that they bulge beyond the anus. This is often quite painful, but it is usually not dangerous.

Although the exact reason someone develops hemorrhoids is often not known, causes include chronic straining during bowel movements due to constipation, sitting on the toilet for long periods of time, pressure due to pregnancy or weight gain and chronic diarrhea. Diagnosis is done via a visual or digital examination of the anus, or with an endoscopic device, which is a thin flexible tube that allows the physician to closely examine the anal canal.

When it comes to treatment, we believe that the first approach should be adjustments to behavior and lifestyle. It’s important to avoid sitting on the toilet for long periods of time, which puts pressure on the rectum and anus. Don’t spend more time on the toilet than it takes to urinate or complete a bowel movement. For some people, a change of diet may be needed in order to deal with chronic constipation. This includes drinking plenty of water for adequate hydration, and eating lots of fresh greens, fruits and vegetables to get the insoluble fiber that makes stools softer and easier to pass. Using a Squatty Potty, a raised platform that turns the seated position on a toilet into a squat, can result in less straining during a bowel movement.

As you’ve discovered, creams and ointments can help to ease symptoms like swelling and itching. However, they don’t cause hemorrhoids to heal. Hemorrhoids often go away on their own. But when lifestyle methods aren’t enough, or fail to adequately manage symptoms, then the conversation will turn to surgery, known as a hemorrhoidectomy, to address the affected tissues. Hemorrhoidectomies are usually done on an outpatient basis, which means you go home the same day.

One final note -- whenever you have anal bleeding, it is important to see your doctor for an exam. We recently had a patient who came to us with bleeding hemorrhoids. Thanks to additional testing, it was discovered to be a rectal cancer, and the patient was able to seek appropriate treatment.

(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.)