SATURDAY, March 12 (HealthDay News) -- Asthma is becoming much more common in the United States and people should know and respond to the basic symptoms before they are faced with a potentially life-threatening attack, experts advise.

"Each day, thousands of people end up in the ER because of poorly controlled asthma. Many don't understand that asthma is a chronic condition that needs to be managed regularly," Dr. Sandra Schneider, president of the American College of Emergency Physicians, said in an ACEP news release.

In the past 30 years, the number of people in the United States with asthma has tripled to nearly 25 million, according to the U.S. Centers for Disease Control and Prevention. In 2007, there were nearly 17.5 million asthma-related emergency department visits nationwide.

Triggers that can make asthma worse include: smoke; dust mites, pollen and mold; perfume or scented soap; respiratory infections; and extreme weather conditions.

According to the ACEP, recognizing and responding to the following warning signs can help people avoid an asthma emergency:

  • Wheezing and/or coughing that disturbs sleep at night.
  • Having to use a quick-relief inhaler more than twice a week.
  • Taking time off from work or school due to breathing problems.
  • Consistently having trouble breathing during physical activity.
  • Inability to take part in normal, everyday activities.
  • Needing urgent or emergency care.

It's especially important for parents to recognize these warning signs in children with asthma, said the ACEP news release. About 7.1 million children in the United States have asthma, according to the CDC, and asthmatic episodes account for 17 percent of children seen in emergency departments.

"It's a serious disease but it's treatable. If you consult with your doctor and manage it properly, your chances of needing to visit the emergency department in the future because of it will go down," Schneider said.

More information

The U.S. National Heart, Lung, and Blood Institute has more about asthma.