It's estimated that one in 12 Americans suffers from some form of asthma, a chronic but reversible lung disease that causes inflammation and constriction of the airways.
A person suffering an asthma attack might wheeze and cough, struggle for breath and feel a tightening in the chest. Not every patient who presents with such respiratory symptoms has asthma, though, and vice versa. New studies coupled with a spike in rates over the past decade are fueling growing concerns about the misdiagnosis of the disease.
"It's often underdiagnosed and sometimes overdiagnosed as well, depending on which subset of patients we are looking at," said Dr. Dheeraj Dhotre, a pulmonologist with Colorado Springs Pulmonary Consultants. "Asthma is just talking about a reaction in the lungs. That's the only way we define asthma."
According to the Centers for Disease Control and Prevention, in the eight years after 2001 the number of Americans diagnosed with asthma grew by 4.3 million. Of the patients referred to National Jewish Health in Denver for asthma treatment between 2005 and 2008, however, one in four didn't have asthma. In addition, 70 percent of those patients suffered from other, undiagnosed ailments for which they weren't being properly treated.
"It's very logical for general practitioners to assume most breathing problems are asthma, especially in children," said Tod Olin, a pediatric pulmonologist at National Jewish Health, the nation's leading respiratory hospital. "But there are a lot of breathing problems out there."
For children who actually have the disease, a firm diagnosis can be difficult for a doctor to pin down, for multiple reasons, Dhotre said.
"With children, it's a little bit of a mystery. Other issues can make diagnoses of asthma more difficult and medical professionals don't want to get it wrong," Dhotre said. "If they're wheezing, they're often treated for colds. They get to an allergist or pediatric pulmonologist pretty late."
Once issued, a diagnosis is hard to unmake on the clinical level, even if it's later found to be wrong, he said.
"A patient, if he or she is labeled asthmatic, if it's a misdiagnosis and if they come to the hospital, it's a long process to undiagnose someone with asthma," Dhotre said. "On the other hand, if someone has not been diagnosed with asthma and they present with asthma-like symptoms, sometimes we use therapeutic trials of medications, like albuterol, and do allergy testing ... to find out the triggers for them."
Since the symptoms of obesity can be similar to those for asthma, diagnoses have been found to be especially off among the morbidly obese.
"In the underdiagnosed, when it's diagnosed as allergies or wild illness, they don't get started on the asthma treatment and thereby they don't get the benefit of the asthma medications," Dhotre said. "If they are underdiagnosed, an asthma flare-up could be a life-threatening situation if the patient or the provider doesn't recognize it."
Tests that measure a patient's pulmonary function by exposing lungs to chemicals that commonly trigger asthma can help lead to more accurate diagnoses, Dhotre said. Another promising test measures the amount of exhaled nitric oxide, which the body produces when fighting inflammation. Higher levels are one sign of asthma.
"There's a lot of research going on about other things to make diagnoses of asthma easier," Dhotre said.