A new study offers concrete evidence that allergies are exacerbated by secondhand smoke.

The study, entitled “Challenge with environmental tobacco smoke exacerbates allergic airway disease in human beings” can be found in the Articles in Press area of the Journal of Allergy and Clinical Immunology (JACI) Web site located at http://www.jacionline.org. The JACI is the peer-reviewed journal of the American Academy of Allergy, Asthma & Immunology (AAAAI).

David Diaz-Sanchez, PhD, University of California -  Los Angeles, and colleagues hypothesized environmental tobacco smoke (secondhand smoke) could interact with allergens and alter the immune system’s response. In order to test the hypothesis, 19 nonsmokers with ragweed allergy were recruited for the study.

Each of the individuals underwent a nasal lavage (rinse), and the lavage fluid was collected for testing. Immediately after the lavage, the study participants spent two hours in a chamber where they were either exposed to secondhand smoke or clean air. After another nasal lavage was performed and the fluid collected, each group was exposed to either ragweed or a placebo. Lavages were then performed at 10 minutes, 24 hours, and at 4 and 7 days afterward and analyzed for levels of IgE (the antibody produced in response to allergen exposure) and histamine (one of the substances responsible for the symptoms of inflammation).

Four days after exposure to ragweed/secondhand smoke, levels of IgE were 16.6 times higher in the nasal fluid than for study participants who were exposed to ragweed/clean air. Nasal histamine levels were also 3.3 times higher for those exposed to ragweed/secondhand smoke than those who were exposed to ragweed/clean air.

The authors noted the study provides the first experimental evidence that secondhand smoke can exacerbate allergic responses and also suggest patients with allergies should avoid tobacco smoke.

American Academy of Allergy, Asthma & Immunology (AAAAI)