We don't often think of allergies as an immune disorder, probably because allergic reactions can evoke a wide variety of symptoms, and researchers disagree about the number of people who really suffer from distinct allergies. However, symptoms such as nasal congestion, frequent colds or sinus infections, or severe gastrointestinal problems often point to the allergic response as an underlying cause. In our practice, we consider the possibility of allergic reactions when people are chronically ill but no one has been able to identify an infectious agent or other clear cause. I don't automatically do allergy testing with a new patient, but if I see symptoms suggestive of allergies, it is easy to do a skin-prick test with a panel of common allergens. I've had many satisfied patients who were pleased to find out that their seemingly intractable problems could be solved by avoiding an allergen.
Many respiratory ailments have an allergic basis.
These include asthma, chronic bronchitis, hay fever, and frequent colds or sinus infections. A common scenario for the development of these problems is as follows. The immune system recognizes an allergen in the environment, and antibodies of the immunoglobulin E class are produced. These antibodies are unique in that they can signal other cells of the immune system to release a compound called histamine. Hay fever brings about a runny nose and fluid in the windpipe, and the resulting coughs and sneezes are an attempt to expel the allergens from the breathing passages.