These observations of early mast cell accumulation, elevated serum IgE, and consequent painful sensitivity in response to MI exposures are congruent with similar outcomes we have previously described in mice exposed to commonly used laboratory haptens Ox and DNFB [7,8,9], and suggest that this ubiquitous household preservative can induce allergy-provoked pain. The gene discussed is IGHE; the disease is allergic disease.