Not until 1915 did bronchial asthma, hay fever, urticaria and certain forms of eczema or inflammation of the skin come to be called allergic disorders. At that time the idea of sensitization and reaction of the body to certain foreign substances was established as a reality. Later other conditions such as serum sickness, reactions to drugs, and some blood vessel disturbances were added to the list.
Allergy today is conceived to be the results of contact of a foreign substance with its specific antibody in the human system. Repeated exposure to the foreign substance or allergen sets up the excess sensitivity.
Experts distinguish certain allergic disorders as atopic-meaning a strange disease-because they are largely hereditary, because the allergens which set them up are nontoxic substances like pollens or foods, and because the first manifestation is a swelling with accumulation of water in the tissues. The diagnosis of the condition is made by putting the allergen on the skin, whereupon a blister or wheal forms. This accumulation of fluid is due to the release of a substance called histamine. As a part of our progress we have developed antihistaminic drugs. If these are given before making the skin tests, the wheals do not develop.
The majority of people who develop atopic conditions do so before they are twenty years old. The real allergic conditions appear usually after the person affected is thirty years of age or older. Dr. Harry Alexander points out that a child who becomes subject to asthma at the age of five almost surely is hypersensitive to a specific allergen which it inhales or swallows.
Because of the reactions that occur in the skin the use of tests for determining the nature of allergic conditions is standard.
When a person has bronchial asthma, the bronchial tubes are narrowed by spasm of the muscles and excess secretion from the mucous glands. As air is forced through these narrowed tubes a wheezing sound is heard. Air is more easily drawn in than expelled. Since part of the air is trapped, it accumulates and the lungs grow larger. The still air in the lung makes oxygenation more difficult and the blue color that denotes lack of oxygen appears.
This form of asthma runs in families. The patient with bronchial asthma usually reports that he had eczema or hay fever when younger or was sensitive to various substances. The symptoms usually come on and are worse at night. The secretion accumulates at night. Because of the difficulty in breathing, the asthmatic person sits up and bends for -ward with elbows on the table, in which position he breathes more easily.
The asthmatic attack may last for hours or days. It is relieved by the use of epinephrine or adrenalin. Dr. Harry Alexander distinguishes three types of bronchial asthma. The mild form is limited merely to a persistent cough with a few paroxysms of bronchial spasm and wheezing. The second form is most serious, beginning with sieges of coughing at night and proceeding to severe bronchial spasms with shortness of breath. The patient finds difficulty in eating and sleeping and drinking and loses weight rapidly. In the third type, secondary infection comes in and is responsible for additional symptoms.
Bronchial asthma should be treated promptly and seriously in order to prevent the permanent changes that develop in the lungs in long-continued cases. Everything possible must be done to detect and eliminate the sensitizing substance.
About 3,000,000 people in the United States have hay fever. Most cases are due to sensitivity to ragweed pollen. These pollens may be blown as much as fifty miles from their sources. Every area has its own pollens, and charts have been prepared showing the prevailing pollens in each portion of each state.
The allergists say that some time is required to sensitize the individual with hay fever. The antibodies get in the mucous membranes of the nose, in the skin, and in the bronchial tubes so that some asthma may accompany hay fever, and the skin tests are positive for the offending allergens.
For the hay fever patient the first step is to find the pollens to which he is sensitive. This may be done by a series of skin tests. He then has the choice of moving out of the area to a place where he will be free from such contact, or of being desensitized with injections of the offending substance. Usually treatment is begun a few months before the hay fever season begins. Gradually the strength and amount of the injections are increased, so that the patient is receiving large doses by the time the season begins. In some instances treatments are given every two or three weeks all through the year. The use of such methods requires skill and experience, because patients sometimes react most seriously to injections of large doses of the substances to which they are sensitive.
Among other measures used for hay fever is the use of air conditioning, air filters, masks and covering of windows to exclude pollen. Most physicians now supplement the specific treatment with use of the anti-histaminic drugs, which are often remarkably effective in stopping the most annoying symptoms. Vasomotor rhinitis is a condition like hay fever due to sensitivity to dusts or food substances.
In addition to the allergies that localize in the nose and the bronchial tubes, such reactions may come in the stomach and intestines, in the skin and in the joints. They may manifest themselves as headaches and in disturbances of the blood vessels.
The reaction to foods is manifested by swelling, excess secretion, and spasm of the bowel. This is not nearly so frequent as commonly thought. Nevertheless, children react to eggs, milk, or other proteins. Diets from which the offending substances are eliminated stop the symptoms.
Sometimes the taking of foods to which there is sensitivity is followed by headaches due to pressure in the brain from swelling of tissues. Chocolate, nuts, onions and spices, garlic, and similar foods are the most frequent offenders.
Sensitivity to foods may also reveal itself by eruptions on the skin with severe itching and sometimes with wheals or blisters. Similar reactions occur from the taking of glandular substances or, secondarily, from infections. Occasionally sensitivities manifest themselves by inflammation of the eyes, swellings in the internal ear, purpura with blood spots in the skin, inflammations of nerves or eczema. The investigation of such cases with determination of the factors of importance and elimination of exposure to them, requires patience and intelligence on the part of both physician and patient.
People may be sensitive to the injection of serums and respond excessively to the injection of preventive inoculations. Allergists describe reactions called "contact dermatitis" from mascara, the material in dress shields or brassieres, the dyes used on furs or shoes, or the filler used in rayon underwear. Sometimes the drug used to relieve a sensitivity creates a sensitivity to itself.