Rhinitis medicamentosa is a type of rhinitis that is induced by frequent and prolonged use of decongestant nasal drops and sprays. The nasal passages become red, boggy, or pale gray and edematous, and the inflamed membranes are indistinguish­able from other forms of chronic inflammation of the nose, due to overuse of topical nasal decongestants.

A powdered product made from plants of the orris family, orris root was once widely used as a powder base in cosmetics. Be­cause of the number of people with allergic reactions to the root, however, it has been virtually abandoned.

Intal is the trade name for sodium cromolyn, a powder that is in­haled into the lungs. It can be useful both in preventing asthma and as a medication. Intal, however, contains a small amount (20 milli­grams per capsule) of lactose sugar, something your physician, if aware of your condition, will take into consideration. Other than this, there should be no problem in using this medication.

Drugs commonly used to treat allergic diseases act either by sup­pressing the release of mediators from mast cells and basophils (diso-dium cromoglycate acts in this way) or by antagonizing the effect of the mediators on tissue targets (antihistamines). The action mecha­nism of corticosteroids such as prednisone is not known. Recent evidence suggests that corticosteroids may reduce the number of mast cells and basophils in the target tissues. As more is learned about allergic reactions and how mediators act, improved drags can be developed. The simplest, most straightforward way to relieve the symptoms of allergic diseases is to avoid the allergens that cause them. This is done fairly easily when the source of the allergen can be recognized and avoided, as, for example, in the case of a pet cat. When the source is as widespread as ragweed pollen, however, avoidance is not practical. In this century, extracts containing biologically active components of allergens have been used extensively in treating allergic diseases. At first, immunotherapy, the regular, systematic administration of these extracts, was intended to immunize people against the supposed toxic effect of allergens. As the role of hypersensitivity in allergic diseases became known, the concept of hyposensitization was intro­duced, in which successful immunotherapy was thought to result in a reduced level of sensitivity. But it did not result in a complete loss of sensitivity. Later it was shown that immunotherapy induces a new type of antibody, called a blocking antibody. The use of modern immunologic methods has proved that the blocking antibody is an IgG antibody capable of reacting with allergen in the body fluids before it reaches the mast cells and basophils in target organs. Ele­vation of allergen-specific IgG antibody does indeed occur during immunotherapy; this seems important in the successful treatment of allergy to stinging insects. It has also been found that immunotherapy blunts the seasonal booster effect of inhaled allergen on IgE antibody. This effect is followed by a gradual decline in the level of the par­ticular antibody. What is not yet clear is whether these changes ac­count for the relief of symptoms that occurs with successful immuno­therapy for allergy to such inhaled substances as pollen. Another clue to the mechanism of immunotherapy is the recent observation that immunotherapy is accompanied by an increase in suppressor T cells. It seems reasonable to assume that these T cells are related to the changes described above. Furthermore, it is possible that the T cells are also involved in regulating the flow of basophils and mast cells to target organs. If such is the case, perhaps another effect of immunotherapy will be a reduction in the number of sensi­tized cells present in the target tissues of an individual being treated. Further research in the immunologic aspects of allergic diseases should provide a better understanding of their mechanisms and should, as well, put immunotherapy on a more rational basis.

An elimination-challenge diet is a method of determining food allergens by temporarily and selectively eliminating common foods, especially those known to be allergenic, followed by ingestion of the suspected food allergens, one at a time, to see whether they will actually produce symptoms.

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Serum is the yellow liquid part of the blood that remains after cells and fibrin have been removed.

Receptors are sites on cell surfaces where drugs and other chemicals attach, enter, or activate.

Much of the research today consists of studies of allergies in animals. Because certain species develop allergic sensitivity to specific chemicals, they can be used to study the process of allergic sensitiza­tion. Research in animals can also be used to develop new methods of desensitization. Animals are necessary in tests of new drugs, since all new pharmacologic agents must somehow be proven safe before they can be tested in humans.

(wheat-free, milk-free, egg-free, corn-free

(For gluten-free diets, use a cereal-free baking powder and, for the barley flour, substitute 1 1/3 cups rice flour less 2 tablespoons.) Cream together the sugar and shortening. Add the egg substitute and water and lemon juice and beat well. Mix in the mashed bananas. Stir together the flour, mace, baking powder, and baking soda. Add the flour mixture and the Va cup water alternately to the creamed mixture, begin­ning and ending with flour. Grease and flour (with barley flour) a 9-cup mini-Bundt pan. Bake in a 350° F oven for 40 minutes. Cool in pan for 15 minutes. Remove from pan and complete cooling on a wire rack.