As many as one in five people are intolerant to certain chemicals, foods and medical prescriptions, but doctors often miss or overlook those causes in diagnosing illnesses in their patients, new research shows.
The study, out of the School of Medicine at The University of Texas Health Science Center San Antonio, suggests more doctors need to use the clinical tools available to identify chemical intolerances far more frequently than they do.
Dr. David Katerndahl, who led the study published in the Annals of Family Medicine, noted the cause of such intolerances is often unclear, but that shouldn’t matter.
"Apart from the debate over causality, the fact that so many patients meet the criteria for chemical intolerance holds particular relevance for primary care providers," said Katerndahl, a family and community medicine specialist.
Katerndahl and his colleagues said physicians need to know how chemical intolerance affects certain people and that conventional therapies can be ineffective. Many patients improve by simply avoiding certain chemicals, foods and even medical prescriptions, they said. They also noted patients with chemical intolerance go to the doctor more than others, tend to have multiple symptoms and are more apt to have to quit their job due to physical impairment.
The study involved 400 patients surveyed while waiting to be seen at primary care clinics. The researchers asked the patients to respond to 90 questions about their illnesses, mental health and ability to function. More than 20 percent of the patients questioned met the scientific criteria for chemical intolerance. Researchers surveyed patients with chronic conditions such as allergies, asthma, diabetes and heart disease.
Chemical intolerance is not well understood, the researchers noted. But people with chemical intolerance are highly sensitive to common substances such as cleaning products, tobacco smoke, fragrances, pesticides, new carpet and auto exhaust.
Common symptoms include fatigue, changes in mood, difficulty thinking and digestive problems.