Dear Doctors: My husband and I were clearing weeds when I felt a sharp jab on my leg. I thought the weed whacker had kicked up a rock, but it was a bite from a fire ant. The pain was severe, as was the reaction. I got a huge lump, blisters and bright red skin. What can you do for fire ant bites?

Dear Reader: Fire ants are native to South America. More than a century ago, the first of the two species now found in the United States arrived aboard a cargo ship in Mobile, Alabama. Black fire ants arrived in 1918, while red fire ants, also shipboard stowaways, were first observed in the late 1930s. At this time, fire ants inhabit the southeastern and southwestern states, much of California and some of lower Oregon. They spread into new areas by expanding their colonies and are introduced in transported agricultural products.

Both species are extremely aggressive when disturbed. Touch or kick a nest, and the ants respond with a rapid vertical climb, during which they sting their target, often multiple times. They fasten themselves to the skin by clamping down with their powerful jaws, then inject a painful venom into the flesh with the stinger located on their hind end.

The venom can elicit a strong and prolonged immune response. In cases of an allergy, as with a bee sting, the effects of the bite can become life-threatening. However, this is rare.

The symptoms you described are typical of a fire ant bite. The initial stinging pain of the bite is followed by a painful burning sensation from the venom in the sting, which gives the ants their name. The area around the bite quickly becomes inflamed and dotted with itchy red bumps. Within a day, the bumps develop into fluid-filled blisters.

Because a single fire ant can bite and sting multiple times, people are advised to immediately and briskly rub them off of the skin. At the same time, step away from the area where you have received the bite, as additional ants may have been disturbed and can also respond with an attack. Wash the area to get ahead of possible infection.

Over-the-counter antihistamines can help blunt the initial effects of the bite. Hydrocortisone cream and ice packs can also ease pain and swelling. In most cases, swelling is localized to the bite and resolves in a few days. If symptoms don't respond to over-the-counter medications, your doctor may advise prescription-strength versions.

The pustules that form around a fire ant bite last a week or more. Infection is possible, so it is important to care for them as you would any wound. This includes keeping the area protected, clean and free from dirt.

When any kind of insect bite causes a severe allergic reaction, it's vital to seek immediate attention. Symptoms include noisy or labored breathing, excessive sweating, nausea, hives or welts, dizziness, unusual weakness, swelling of the face or eyes, slurred speech or chest pain.

(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: If a flight I'm on has turbulence or if it descends too fast and the pressure drops, I get very nauseated. Why does that happen? I've tried motion sickness medication, but it makes me feel like I am in a tunnel. Even the nondrowsy kind knocks me out to where I can’t function. What else can I do?

Dear Reader: As many travelers reading your question know, you have been experiencing motion sickness. Nausea is one of several unpleasant symptoms associated with the condition. Additional effects can include feeling dizzy or lightheaded, sweating, headache and vomiting. These symptoms can arise when someone is a passenger in a moving vehicle, such as a car, bus, train, boat, amusement park ride or aircraft. It's possible, but less common, for the person who is operating the vehicle to also experience motion sickness. For some people, vertiginous visuals in a film can bring on the symptoms.

Motion sickness occurs when the information that your eyes are relaying to the brain differs from what it is learning from the inner ear, the muscles and the joints. Each plays a role in the complexities of spatial awareness, which allows us to remain upright, to move deliberately and to both maintain and regain balance. In the face of conflicting input from multiple sources, the brain struggles to put together a logical narrative. And for some people, the result of this prolonged disconnect is the misery of motion sickness.

While motion sickness medication can be effective, it can have side effects. These include the sedative effect that you have experienced. It also can cause dry mouth, constipation, dizziness, blurred vision and nausea.

For people who can't tolerate medications that contain a drug called dimenhydrinate (check the ingredient labels), which is an antihistamine, those containing another drug, meclizine, can be a better option. It, too, is an antihistamine, but it causes less drowsiness.

If over-the-counter medications aren’t working, ask your doctor if a prescription medication might be right for you. They may also recommend vitamin B6, which can be helpful for nausea.

Many people turn to natural remedies to manage motion sickness. Research shows that ginger and chamomile, as a tea or other beverage or in a hard candy, can help fend off nausea. Some people swear by anti-nausea wristbands, which trigger an acupuncture pressure point and are widely available over the counter.

Behavioral changes are also important. A window seat allows you a view of the horizon. By looking at a fixed point, you give your brain a frame of reference from which to unscramble the mixed signals it is getting. Turbulence can feel more pronounced at the back of the plane, so opt for a forward seat close to or over the wing near the plane’s center of gravity. Use the vent above your seat to circulate the air around you. And be kind to your stomach. Avoid large meals and fatty foods, and stay hydrated.

(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 am a 29-year-old man at a normal weight, and I eat a balanced and healthy diet. I've been having night sweats and sometimes also mild or moderate kidney pain. There is a history of cancer on both of my parents’ sides of the family. I'm not asking for a diagnosis, just advice on how to figure this out.

Dear Reader: With the recent onset of night sweats that are coupled with persistent kidney pain, we recommend that you see your health care provider as soon as possible. The symptoms should be explored, and your immediate family's medical history is a factor, as well.

There are a range of potential causes for the symptoms you have described. However, if they should point to a serious health problem, delaying a diagnosis that can pinpoint appropriate treatment or therapy is not a risk you should take.

Begin with your primary care physician. If you have been seeing him or her for a period of time, they will be familiar with your medical history. And if you have been having regular physical exams, they will also have access to test results that can provide useful information. These include a pair of blood tests -- a complete blood count and a metabolic panel, which are typically part of an annual physical.

The results yield information about how various systems in the body are functioning. These test results also act as a baseline against which the results of subsequent tests can be assessed. Significant differences from previous test results are often an important starting point for a diagnosis. If you have recently changed care providers, you can ask your previous doctor to share your medical records with your new physician.

In addition to evaluating your test results, it is likely that your doctor will ask to review and update your own medical history and that of your family members. It is important that you share the information about a family history of cancer. Even if you have already discussed your medical history in previous visits, going over it again is helpful, not only for the doctor, but also for you. It can jog your memory about symptoms or illnesses you may have previously omitted, and it allows you to fill in more recent details.

A medical history typically includes specifics about allergies, recent illnesses, major illnesses in the past, mental health issues, any surgeries and a detailed record of all immunizations. Be sure to include precise information about medications, as well as any vitamins or supplements you may be using.

When a condition is outside of a primary care doctor's sphere of expertise, they will recommend seeing a specialist. Which type of specialist is determined by the implications of your physical exam and test results. It's a good idea to get several recommendations so you can find the right fit. Important considerations include the doctor's credentials, compatibility with your health insurance, good communication (including with the staff) and their hospital affiliations. But most important, when you are asked to see a specialist, follow through.

(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.)