Secondhand smoke has been linked to a lot of other medical conditions but this is probably the first scientific evidence linking secondhand smoke exposure to worsening allergic symptoms. According to a research published in the recent issue of Journal of Allergy and Clinical Immunology, environmental tobacco smoke (ETS) increases the levels of allergy indicators or markers called IgE in the nasal fluids.

Here are the main findings:

• Four days after exposure to ETS/ragweed, levels were on average 16.6-fold higher than after clean air/ragweed challenge.
• ETS (vs air) promoted the induction of a TH2-cytokine nasal milieu (increased IL-4, IL-5, and IL-13 and decreased IFN-γ production), characteristic of an active allergic response.
• Nasal histamine levels were 3.3-fold greater after ETS/ragweed challenge than after clean air/ragweed challenge.

See the summary from Ivanhoe or the abstract from the JACI article.