Acetaminophen Allergies

Acetaminophen, also known as paracetamol, is an over-the-counter pain reliever and fever reducer used to treat headaches, muscle aches, colds, arthritis and other minor aches and pain. In the last decade, several studies suggested the relation between acetaminophen and allergies, and as of 2010 a clinical trial is underway to determine if acetaminophen directly causes allergies.

Evidence

Recent evidence found the most compelling link between acetaminophen use and risk of asthma and allergies, according to study in the August 2010 issue of the "the American Journal of Respiratory and Critical Care Medicine." Over a one-year period, researchers studied more than 300,000 adolescents in 50 countries, asking them to report how often they took acetaminophen. A previous study involving 1,000 adults and children in Ethiopia published similar results in the October 2005 "Journal of Allergy and Clinical Immunology." A summary paper in the November 2009 issue of "Chest" also found an increased risk of asthma with acetaminophen use in children and adults.

Relative Risks

According to a MedlinePlus report on the "American Journal of Respiratory and Critical Care Medicine" study, the risks of having asthma and rhinoconjunctivitis was 2.5 higher among teenagers who used acetaminophen at least once a month, or frequent users, compared to those who do not use the drug or non-users. The risk of eczema had a 99 percent increase for frequent users compared to non-users. Teenagers who used acetaminophen at least once a year still reported an increased risk of asthma or allergies compared to non-users.

Symptoms

According to this study, symptoms of allergy related to acetaminophen use included red, itchy and recurrent rash in several parts of the body, red, itchy, watery eyes, runny or stuffy nose and itchy throat. Asthma symptoms included wheezing, difficulty breathing and cough. Frequent users of the drug reported more severe respiratory symptoms, including extreme wheezing that disturbed sleep and limited the patients' ability to speak.

Considerations

Although evidence from these studies supports the relation between acetaminophen and allergy and asthma, the study's main author Dr. Richard Beasley, in his interview with MedlinePlus, cautions that a randomized controlled trial--which has yet to be done--would be the gold standard for determining whether acetaminophen causes allergic reactions.

Clinical Trial

As of 2010, Tel-Aviv scientists are conducting a randomized clinical trial on the effect of paracetamol, also known as acetaminophen, on asthmatic and healthy children, reports ClinicalTrials.gov, a National Institutes of Health registry of all clinical trials conducted worldwide. The researchers suggest that a single dose of acetaminophen is enough to cause significant, measurable changes in function and airways of the lungs. The trial is scheduled to end by March 2011.