Allergy

Is there any more grotesque example of an imbalance between the cost and benefit of an immune response than anaphylaxis? On exposure to even minute amounts of material containing the offending allergen (such as peanuts), the unfortunate subject experiences within minutes a reaction that can include nausea and vomiting, hives, difficulty breathing and rapid circulatory collapse. Although anaphylaxis, fortunately, is uncommon, allergic disorders in general are both very common and relentlessly increasing in incidence. In the US alone, 8–10% of children now suffer from asthma — a syndrome characterized by reversible airway narrowing, airway hyper-reactivity and inflammation of the airways. The annual cost of treating asthma in the US is estimated to be $6 billion. When one adds in subjects with other allergic diseases, such as hay fever (allergic rhinitis) and atopic dermatitis (also known as eczema), roughly 20–25% of citizens of the industrialized nations are affected.