What is Allergic Rhinitis?

ALLERGIC RHINITIS

by Allan M. Wachter, M.D.

Allergic Rhinitis, “hay fever“ as it is commonly called, is by far the most common of all allergic diseases. Over 25 million children and adult Americans are affected. It is the most common cause of poor concentration in school by children and over 3.5 million days of work are missed by adults each year.

Allergic rhinitis is divided into two categories: seasonal allergic rhinitis due to exposure to pollens and mold spores, and perennial allergic rhinitis due to house dust mite debris, insect parts, animal dander, and salivary proteins.

The most important concept to understand is that allergic rhinitis occurs because of repeated and persistent exposure to allergens (substances foreign to the body.) Allergists suspected this as much as 85 years ago. When those allergists taught their patients avoidance measures, they were more effective than their counterparts using medicines of that bygone time.

New research has now confirmed these suspicions that avoidance of allergens should be the cornerstone of our treatment plans. This is a underscored in view of new and old studies demonstrating that 30-40% of patients with allergic rhinitis are prone to asthma. Allergists hope that with careful avoidance of dust, mites, cockroaches, cats, and environmental contaminants, the incidence of allergic rhinitis and even asthma may be significantly lowered.

Allergic rhinitis is best diagnosed not by ordering tests alone, but by your doctor obtaining a careful history of your symptoms, with specific attention being made to your home environment, hobbies, and job. Laboratory tests consisting of skin test and/or RAST (blood testing) should be ordered only to confirm clinical impression of your doctor.

From a scientific point of view the main allergy cell in the body is the mast cell. Within the mast cell are small granules containing histamine. When a mast cell is triggered by allergic antibodies (IgE) this cell bursts and releases histamine. This is the chemical mediator responsible for itchy eyes and skin, runny noses, and even wheezing in asthma.

Probably the most important role the allergist plays today in the treatment of allergic rhinitis is in patient education. Education is of particular concern and an integral component of the overall therapeutic plan when dealing with chronic diseases. Your allergist will review proper environment control measures, the use of medication and their side effect profile, the use and abuse of steroids, when immunotherapy (allergy shots) is indicated, and an action plan for when you need intervention.

The treatment of allergic rhinitis can be broken down into four major categories:

  1. Allergen avoidance—environmental control measures.
  2. Preventative “anti-inflammatory” therapy—nasal steroids and cromolyn.
  3. Rescue therapy—decongestants and antihistamines.
  4. Immunotherapy.

The key to successful therapy is consistency. Constant vigilance with home and work environmental control measures cannot be overemphasized. Topical nasal steroids are most effective when used on a regular daily basis. A clear and important distinction must be made between oral and nasally-administered steroids. With the current steroids nasal preparations available in the U.S., neither changes in bone growth nor hormonal imbalances (adrenal suppression) have been detected when patients use therapeutic doses. On the other hand, long-term oral steroids (greater than one month) or injected steroids have been shown to cause potentially serious adverse effects.

Antihistamines have improved significantly in the last decade. The new second-and third-generation drugs are nonsedating and do not interfere with performing motor tasks. Recently, certain second generation antihistamines have been reported to cause heart arrythmias and you should consult your doctor about these potential problems. Safer substitutes for these drugs exist.

Topical and oral decongestants provide rapid relief of nasal congestion. Significant numbers of patients become addicted to topical nasal preparation and develop rebound nasal congestion. High doses or oral decongestant preparations are associated with caffeine like stimulatory side effects, e.g. tremors, anxiety, and even high blood pressure.

One of the new topical agents is ipratropium bromide. This drug works differently than steroids by acting on the nasal nervous system and quickly drying up the nose. This drug cause neither rebound nasal congestion nor nasal addiction. It may be best used in conjunction with a nasal steroid.

Multiple controlled clinical trails have clearly shown that immunotherapy is effective for allergic rhinitis associated with pollens, molds, dust mites, and cat sensitivity. This therapy is best reserved for those patients having failed conservative medical therapy.

In summary, avoidance of allergen is the key to lowering one’s risk of developing allergies. If this is impossible to achieve, since we have no control over the air we breathe, then the newer medications and/or immunotherapy may be an option worth pursuing.

Posted in: Rhinitis

Allergy and the Environment