Both allergic rhinitis (allergy that is caused by caused by reaction to substances such as pollen, mold, pets, or food) and asthma (constriction and inflammation of airways leading to the lungs) are increasing in prevalence worldwide, adding considerably to the cost of health care, reports the International Study of Asthma and Allergies in Childhood. Experts believe that allergy and asthma often occur together because both are physiologic responses to the same influences, such as an allergen or environmental factor. Recently, researchers have focused on the link between the two conditions.
Types
Exercised-induced asthma is triggered by exercise, while nonallergic asthma can be caused by cold air or infections, reports the Mayo Clinic. Gastroesophageal reflux disease (GERD) is another established trigger for asthma. The most common form of asthma, however, is allergic asthma, which is triggered by a reaction to an allergen.
A Link in Risk Factors
The risk for allergic rhinitis is higher in people who have asthma or have a family history of allergy and asthma, reports the Mayo Clinic. Similarly, having allergies or a close relative with asthma, hay fever or other allergies increases the likelihood that a person develops asthma. According to ARIA, the Allergic Rhinitis and Its Impact on Asthma workshop, in children, allergic rhinitis often precedes the appearance of asthma or occurs at the same time.
"One Airway One Disease" Theory
Researchers subscribe to the concept of "one airway one disease" in which rhinitis and asthma are manifestations of a single chronic inflammatory syndrome, ARIA reports. They link the upper and lower airways, emphasizing the respiratory tract as a single organ. According to this theory, allergic rhinitis is the early clinical manifestation, primarily affecting the upper airway, while asthma, the later form, affects the lower airway. In addition, people with the most severe rhinitis are much more likely to have asthma. Nevertheless, ARIA cautions, these are two distinct conditions and that not all people with allergic rhinitis develop asthma.
Symptoms
Symptoms of allergic rhinitis reflect its presence in the upper airway and include blocked and runny nose, watery eyes, sneezing and cough. The symptoms of asthma, which include shortness of breath, tightness in the chest, coughing and wheezing, reflect its presence in the lower respiratory tract.
Implications
Treating allergy promptly may alleviate or forestall onset of asthma, which can be more serious. Some agents relieve both conditions. ARIA reports that nasal steroids improve both allergic rhinitis and asthma, and may, if used promptly, prevent the onset of asthma altogether. Similarly, children with pollen allergy are less likely to get asthma if they have allergy shots. The Mayo Clinic suggests that these shots, also called immunotherapy, gradually reduce the patient's immune system response to allergens that also trigger asthma.
Recommendations
ARIA issued new guidelines for managing allergy and asthma in 2008. They recommend that patients with persistent allergic rhinitis be evaluated for asthma by history, chest examination and, if possible, assessment of airflow obstruction before and after bronchodilator. Similarly, physical exam of upper airway and history for allergy is recommended for patients with asthma.
References
- "Allergic Rhinitis and Its Impact on Asthma (ARIA) 2008 Update"; Allergy. Bousquet J, et al.; 2008
- "Relationship Between ARIA Classification and Drug Treatment in Allergic Rhinitis and Asthma"; Allergy; 2007
- 'Worldwide Time Trends in the Prevalence of Symptoms of Asthma, Allergic Rhinoconjuctivitis, and Eczema in Childhood: ISAAC Phases One and Three Multicountry Surveys"; Lancet; 2006
- MayoClinic.com: Allergies and Asthma: They Often Occur Together
