Allergy Overview
In much the same way that a teenager will over-react to constructive criticism from a parent, our immune systems can be hypersensitive to otherwise innocent environmental exposures. This is not entirely felt to be inappropriate, as it appears that our bodies are actually trying to clear invading molecules when the allergic response begins. Antibodies, which are classified as groups A, D, E, G, and M, are responsible for keeping us healthy. The inappropriate reaction involves the overproduction of Immunoglobulin E (IgE) and the cascade of allergic symptoms begins.
This overproduction of IgE is a very common phenomenon. There are over forty-one million people in America who suffer from nasal allergies. The allergies may be to allergens that reside inside or outside our homes; the allergens (triggers) range from dust mites, chemicals, and animal dander that are typically found inside to grass pollen, tree pollen, weed pollen, and mold spores that are found outside. From a public health point of view, allergic rhinitis (rhin meaning nose, itis meaning inflammation) is the third or fourth most expensive disease in the country. It accounts for more days missed from work or school than any other disease. Fortunately for all of us, our understanding of allergic rhinitis has progressed a long way; with proper care, allergic rhinitis is a disease that we can manage effectively.
The triggers or irritants that cause allergic rhinitis as mentioned above can be either inside or outside your home. The mechanism of action is the same for both. First a sensitive individual inhales one or more of these triggers; then the mucous membranes that line the nose, throat and bronchi recognize the offending protein as being foreign. In those people with a tendency toward allergies (people with sensitive airways), this recognition or sensitization with the offending protein causes a build up of antibodies (IgE) against these offending proteins, and these antibodies coat mast cells and other immune related cells in the affected area. On subsequent exposures to the same offending proteins, these same mast cells release or stimulate chemicals-histamine, leukotrienes, and others that cause the congestion that leads to the typical symptoms of allergy: the stuffy, runny or itchy nose and the associated symptoms or itchy, runny eyes, post nasal drip and cough.
Most of us are quite familiar with these symptoms. The symptom that is most often reported by all allergy sufferers, however, is actually fatigue, due to restless sleep. Also, patients frequently complain of a scratchy or sore throat. In the office, healthcare providers are able to quickly identify potential allergy patients by others findings. Most commonly, they have dark circles under the eyes called allergic shiners, which are often mistakenly thought to be due to simply a lack of
sleep. These are more likely the result of pooling of venous blood in the tissue beneath the eyes as a result of tissue congestion in the layers below. Patients are also usually puffy in the area of the shiners, causing a Denne-Morgan fold, or crease. Constant rubbing of the nose, also known as the allergic salute, causes a crease across the bridge or transverse nasal crease to appear. If you look carefully, you'll see these on most, if not all, allergy sufferers.
If both your parents have allergic rhinitis, you have an eighty percent chance of having the same problem; if only one parent has allergic rhinitis, you have a forty percent chance. Thus there is a tendency for allergic rhinitis to be inherited; however, twenty percent of patients have no strong immediate family history. There is ongoing research as to why we seem to have more problems with allergic rhinitis now than we did two generations ago. Certainly, we have more irritants to contend with, and the need for better-insulated homes has reduced the replacement of fresh air in our homes and buildings. For whatever reason or reasons, we are experiencing more allergic rhinitis than ever before. Therefore, it is important for us to recognize what is happening and how we intervene.
The onset of allergy symptoms is variable. In children, the most common age of presentation to the doctors' office is at an (incredibly young) age of 4 years. At times, we may even recognize allergic shiners or Denne-Morgan fold mentioned above in babies less than a year of age. Some studies show that 90% of pediatric allergy patients have been to the doctor by age 6. This means that the majority of patients are affected throughout their school years. This presents special problems in the successful treatment of this condition, as the alertness of students is paramount in the consideration of side effects of medications.
The treatment of allergies is an evolving field with new discoveries and therapies being tried out constantly. The most popular medication is antihistamines, which have been also called Histamine-blockers in an effort to make them sound more important. These products interfere with the single most abundant chemical in the entire allergic cascade. Unfortunately, there are often side effects, including sleepiness, which has prompted the creation of a lucrative business of creating less sedating versions of antihistamines. More recent research also indicates that there are plenty of other chemicals involved in the allergic phenomenon and newer classes of medications have climbed aboard the bandwagon including nasal steroids, mast cell inhibitors, inhaled antihistamines, and leukotriene modifiers. As a more invasive intervention, immunotherapy, a.k.a. allergy shots, is given after the identification of specific allergens.
The Testing Dilemma
Patients and parents frequently ask to have allergy tests performed to identify specific allergies to environmental factors. While these are crucial when dealing with food, insect, and medicine allergies because of the potential severe reactions with these hypersensitivities (i.e. anaphylaxis), the usefulness of allergy testing pales when used for the identification of common, seasonal or perennial allergies. The technical aspects of allergy testing and the validity of the skin scratch tests has been questioned and studied for years. The attainment of reproducible results and the production of reliable, standardized allergens for use in testing have been a holy grail in Immunology. Frequently patients are found to be allergic to everything on a panel (an unlikely situation and therefore a useless result) or to nothing on a panel (an unbelievable result given the symptoms which prompted the testing in the first place). No matter what the result is, unbelievable, unlikely or even accurate and believable, the same medications are used in all patients. There are no antihistamines that are only good for pets or trees, etc. Also the identification of specific allergens does not truly help identify what each patient is suffering from at a given visit. Invariably, we have to rule out causes that make no sense. So a pet allergy is unlikely if no animals are in the house and grass allergies are unlikely in Massachusetts in January. The most common allergens are easily categorized by date and we can usually determine what causes the sniffling just by looking at a calendar.Treatment
To summarize, alert patients and parents armed with a simple calendar can easily identify seasons that are problematic and quickly identify the most likely cause of the allergies. The treatment can begin immediately with the full armamentarium of medications since they are NOT cause specific. Your primary caregiver (PCP) has access to all the same drugs that allergists have. The identification of specific allergens is mostly useful as a scholarly procedure, but usually have NO effect on the outcome of treatment. Exceptions include the removal of pets, plants, rugs or other offending agents and the possible installation of dehumidifiers. Clearly, allergies to trees and grasses pose an insurmountable obstacle, as we cannot removal all the pines in the South Shore. With the calendar that you use to tract the severity of your or your child's allergic symptoms, we can create a treatment plan that anticipates your worst seasons and provides appropriate care for each of them. This plan will include avoidance, prevention (link to how to provide a clean bedroom), antihistamines, nasal cromolyn or steroids, leukotrienes inhibitors, and perhaps decongestants.
