Dear Doctor: Is it safe to use an insect repellent with DEET on my 5-month-old? Here in Tennessee, we're approaching prime mosquito season, and we want our little boy to be able to play outside without getting all bitten up.

Dear Reader: There's nothing like the thin, high whine of a mosquito to let you know your picnic or hike or nap on the porch is about to be ruined by slapping, itching and scratching. Unfortunately, mosquitoes are also known carriers of serious diseases. West Nile virus and St. Louis encephalitis have been diagnosed in some areas of the United States. The Zika virus, while rare in the United States, is also a mosquito-borne disease.

According to the Centers for Disease Control and Prevention, insect repellents that contain DEET are safe to use on children 2 months old and older. DEET, which is shorthand for (deep breath) N,N-diethyl-meta-toluamide, is the active ingredient in a wide array of insect repellents.

DEET does not kill insects. It works by blocking the sensory mechanisms that tell insects that something delicious is nearby. Instead of detecting the chemical markers we humans emit in our breath and sweat, the bugs smell ... nothing. They pass us by.

There are specific guidelines you should follow when using DEET on a child. The CDC recommends that you never use a product with a concentration of more than 30 percent DEET. The percentage of DEET in a product doesn't make the insect repellent stronger or more potent; what that number measures is the length of time the insect repellent will be effective.

Products with concentrations of 10 percent keep bugs at bay for about two hours. Those with 21 to 25 percent DEET provide between five to eight hours of protection. And, please note -- current recommendations state that children should not have more than one application of DEET per day.

Although some insect repellents with DEET have sunscreen mixed in, it's best to steer clear of those. Sunscreen must be reapplied throughout the day to be effective. However, since kids should only get one application of DEET per day, the mixed product is of limited use. It's best to start with a base layer of sunscreen and then add insect repellent. You can then add more sunscreen throughout the day as needed.

Insect repellent should be applied to exposed skin and to clothing. When using a spray, apply it outdoors and be sure to keep it away from food. Make sure neither you not your child inhales the product.

We find that while a spray works well on clothes, insect repellent wipes are great for precise applications to a child's wriggling body. And never put insect repellent on a child's hands, which so often find their way into mouths and eyes. Once back indoors, wash the treated skin with soap and water. Treated clothes should be washed before wearing again.

One final thought: While repellents are a great tool, give them a boost by keeping kids in long-sleeved pants and shirts when in the buggy great outdoors.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I have played tennis for many years, but have been unable to play over the last year, due to tennis elbow. Would acupuncture help?

Dear Reader: Lateral epicondylitis, or tennis elbow, is a tendon inflammation at the elbow. You don't have to play tennis to develop the condition, but the specific motion of hitting a ball with a tennis racket is, unfortunately, an effective way of doing so. There are many different types of treatment for tennis elbow, including anti-inflammatory medications, physical therapy, ultrasound, platelet-rich plasma injections and steroid injections.

As for acupuncture, a review of multiple studies published in the British Journal of Sports Medicine attempted to answer your question. One of the studies found significant pain relief with acupuncture compared with placebo. Overall, reduction of pain was 55.8 percent in the acupuncture group and 15 percent in the placebo group.

However, another study showed an immediate improvement of symptoms with acupuncture after two weeks, but no difference after two months compared to placebo. Lastly, a study comparing acupuncture to ultrasound therapy for tennis elbow found no difference between the two treatments.

Overall, the authors concluded that acupuncture was helpful for tennis elbow, but it did not have a sustained response, lasting only two to eight weeks.

A 2015 study combined results from six different studies. Two of the studies compared real acupuncture with sham acupuncture, which involves placing the needle in non-traditional acupuncture points at random. The authors found a benefit with standard acupuncture compared to sham acupuncture. Also, there were conflicting studies on whether acupuncture with electrical stimulation was beneficial or not.

One other review from 2002 showed that acupuncture for tennis elbow did have immediate benefit, but the authors could not conclude a long-term benefit.

Now, I have to acknowledge that I've been performing acupuncture for tennis elbow for the last 12 years and have seen that the treatment has been beneficial for the majority of patients. I have treated these patients with non-traditional acupuncture points at the tendon insertion of the elbow and have used electrical stimulation. I also add traditional acupuncture points. It is difficult for me to assess how much of the benefit is from the acupuncture, how much is from physical therapy and how much is just the tincture of time.

The studies do appear to show pain relief, but I feel that acupuncture should be combined with physical therapy. The bottom line: Acupuncture is one of many therapies that can help the pain of tennis elbow.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Can you give me some ideas on how to lose weight while using a wheelchair? I'm 66 and need a wheelchair to get around. When the distance is short enough, I use crutches. I'm on a tight budget, but try to work out as much as I can, with very little results. I'm getting depressed because nothing seems to work.

Dear Reader: One look at the multibillion-dollar weight-loss industry, and it's clear that staying fit is difficult for many of us. And while limited mobility certainly adds to the challenge, with creativity and determination, you can win this battle.

When you use a wheelchair, it's particularly important to get fit and to maintain a healthy weight. Even a few excess pounds can make it more difficult to get into and out of a wheelchair. In that same vein, you need your shoulders, arms and abs to remain strong so you can easily move into and out of the chair, and to prevent injury as you do so.

Let's start with what you eat. Focus on a diet made up of a variety of fresh fruits and vegetables, lean proteins, dairy products, healthy fats, legumes, whole grains and leafy greens. Limit added sugars, and cut out empty calories like sodas and processed snack foods. The key here is to adjust your diet to your level of physical activity.

One tool that really works (and takes a bit of courage to do honestly) is keeping a food diary. Even if just for one week, write down everything that passes your lips. The details will jolt you into awareness and, quite possibly, motivate you to make some changes.

As for exercise, the days of the sedentary wheelchair-user are over. There are several exercises you can do from your chair.

With a pair of hand weights, you can keep your biceps, triceps, pectorals and even your abs strong and toned. Resistance bands are another way to maintain strength and range of motion.

An exercise ball is an excellent workout tool. Hold it above your head and, as you engage your stomach muscles, slowly rotate from left to right and back again. Lift the ball above your head and slowly lower it, again engaging your abdominals. Hold the ball above your head, once again engaging your abs, and perform slight tilts to the points of the compass.

With all of these, the idea is to start slow and gradually build up repetitions. Stop if you feel any pain. And be sure to drink water and stay hydrated.

Is there a senior citizen center in your area? Many of them have exercise and yoga classes that can be adapted for someone using a wheelchair. Some even have sports teams that will make room for a rolling athlete.

A challenge for all of us as we get older is social isolation. A group activity can help you feel connected, which will raise your spirits and keep you motivated.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)