(HealthDay News) -- Hives are the result of an allergic reaction. They typically go away without treatment, but can be an itchy nuisance.

(HealthDay News) -- Swollen gums are relatively common, but can signal an underlying health problem.

TUESDAY, Aug. 17 (HealthDay News) -- Nearly 40 percent of Americans with major depression also have brief but recurring episodes of manic behavior, a new study suggests.

TUESDAY, Aug. 17 (HealthDay News) -- One in five people with a condition known as body dysmorphic disorder (BDD) undergo cosmetic procedures, but only 2 percent of them experience a reduction in the severity of their condition after their treatment, researchers say.

TUESDAY, Aug. 17 (HealthDay News) -- Positive brain changes take hold after just 11 hours of practicing a form of meditation, the results of a new study suggest.

TUESDAY, Aug. 17 (HealthDay News) -- Difficulty swallowing (also called dysphagia) is associated with poor outcomes in hospital patients, researchers warn.

TUESDAY, Aug. 17 (HealthDay News) -- When doctors make mistakes, admitting the error, saying "I'm sorry" and offering compensation may go a long way toward preventing malpractice lawsuits, new research shows.

TUESDAY, Aug. 17 (HealthDay News) -- The organization known as Doctors Without Borders, or Medecins Sans Frontieres, performed nearly 20,000 procedures in countries with limited resources over an eight-year period, and reported an extremely low operative death rate, a new study has found.

TUESDAY, Aug. 17 (HealthDay News) -- A surgically implanted antibiotic-infused sponge doesn't lower the rate of sternal wound infections in patients who've had heart surgery, a new U.S. study has found.

TUESDAY, Aug. 17 (HealthDay News) -- Women who drink regular beer may be increasing their risk of developing psoriasis, an autoimmune disorder affecting the skin, new findings suggest.

TUESDAY, Aug. 17 (HealthDay News) -- Deaths from a severe type of heart attack rise by about 10 percent for every hour of delay between the time the patient calls for an ambulance and the time that patient is treated in the hospital, a new European study finds.

TUESDAY, Aug. 17 (HealthDay News) -- Poultry litter can be a significant source of arsenic in the farm field runoff that finds its way into streams and rivers, new research indicates.

TUESDAY, Aug. 17 (HealthDay News) -- Less invasive biopsies done with the help of imaging to guide the needle now make up the majority of biopsies being done, a new study finds.

Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

TUESDAY, Aug. 17 (HealthDay News) -- The number of U.S. teenagers experiencing hearing loss increased about 30 percent from 1988 to 2006, so that one in five teens now has lost some hearing, researchers report.

(HealthDay News) -- Here are the latest clinical trials, courtesy of ClinicalConnection.com: