Considerations in the prevention of seasonal allergic rhinitis

Townsend Letter for Doctors and Patients, May, 2005 by Jason Barker, Chris Meletis

As this issue covers the role of inflammation in several disease aspects, the authors thought it fitting to apply this topic to seasonal allergic rhinitis, otherwise known as 'allergies' or 'hay fever'. Seasonal allergic rhinitis, or for that matter perennial allergic rhinitis (defined as allergic rhinitis lasting 9 or more months of the year) is an inflammatory condition marked by inappropriate immune responses to benign environmental substances. Of all cases of allergies, the perennial variety occurs in 40% of all those affected. The allergens in these cases are typically those with no or little seasonal variation, such as cockroaches, dust mites, indoor molds, and animal dander (fur, feathers, skin, urine). Consider the numbers surrounding this inflammatory condition:

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* Based on the results of skin test allergies only, 40 to 50 million Americans are affected with allergies, making it the 6th leading cause of chronic disease in the US, (1) or 20% of the entire US population. (2)

* Of those affected by allergy in general, close to 36 million people have seasonal allergic rhinitis, (3) leading to 16.7 million visits to health care providers each year. (4)

* The approximate overall cost of allergic rhinitis in the US in the year 1996 alone was 6 billion dollars. (5)

Conventional medical options for this condition are diverse and include blockage of histamine receptors (antihistamines) and stabilization of cells that release this compound (mast cell stabilizers); steroid therapy (nasal and sometimes systemic steroid preparations); and immunotherapy. Immunotherapy is a particularly interesting approach; it consists of a preventive and anti-inflammatory approach to allergies by injecting gradually increasing amounts of the allergic substance into the person, in hopes that the minute increases of allergens will lead to a less sensitive immune system. While this sounds like homeopathy, it is not but does follow a similar line of thinking in that small substances of offending substances, when introduced into the body, will stimulate it into overcoming symptoms.

While all of these approaches have their merits and downsides, they are not necessarily applicable or entirely curative for all people suffering from allergic disease. More importantly, those suffering from one allergic condition are highly likely to be affected by others such as asthma and eczema. These three conditions, allergies, asthma and eczema are referred to as atopic disease and the literature is extensive regarding prevention and alteration of the immune response in these conditions. Giving due attention to all of these approaches is best served by addressing them in a larger compendium; the following are highlights of some of the more popular approaches to allergy prevention and control. (Please see the May 2004 issue of TLfDP for a look at inflammation and asthma).

Prior to treating allergies, the differentiation between true allergic responses and sensitivity must be established. Allergy is defined as an acquired, abnormal immune response to a substance (the allergen) that does not normally cause a reaction, resulting in a broad range of immune (inflammatory) responses. Sensitivity is defined merely as 'susceptibility to a substance'. More specifically, this means that a substance (most typically benign as well) may lead to physiologic perturbations in any number of ways. These include, but are not limited to, migraines, apthous ulcers (canker sores), bedwetting, itching, etc. It is important to make this distinction because both diagnosis and treatment may be completely different in this case.

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Antigenic Load and Food Allergy

While the causes of allergic rhinitis are often obvious (i.e. allergies occur for most people during specific seasonal time periods associated with plant pollens, etc), uncovering what makes the immune system respond in this way is key. One prevailing theory is that of antigenic load, whereupon it is hypothesized that an excessive amount of antigenic stimulus overwhelms the immune system, leading to inflammatory responses. For instance, exposure to small amounts of allergens may not typically amount to symptoms, until simultaneous exposure to a number of antigens leads to "spillover" of symptoms. It is thought that in this manner, the immune system can deal adequately with substances that it perceives as allergens when exposed in limited quantities, however when continually bombarded by allergens, or presented with several different allergens, the immune system is overwhelmed, and as such, symptoms appear. Likewise, repeated chronic immune response to allergens can overwhelm the immune system when we are tired, stressed, or at otherwise less than optimal health. And, it may be possible that sensitivities may contribute to the 'load' mentioned here as well. While much of this is speculative theory, it makes great clinical sense when confronting allergy symptoms.

One of the most direct ways to lighten the antigenic load is by identifying and removing food allergens. A whole subject unto itself, food allergies and sensitivities play a key role in resolving many physical symptoms in people, including allergic responses. When we look at foods as a culprit, this makes complete sense, as they comprise the largest pool of antigenic challenges to the immune system. (6) (Please see the TLfDP on food allergies). Additionally, food groups are very consistent in the majority of people as diets rarely vary from 10 different food types on a weekly basis. Continuous exposure to sensitivities or allergies in this fashion is an understatement. Food sensitivities and allergies themselves set up the immune system for even more reactivity toward other substances.