"PEOPLE," wrote the late humorist Robert Blenchley, "can have sunburn, hangnails or even ordinary head colds, and their more fortunate mates will say: 'Aw, that's too bad! Why don't you just take the day off and go home?' But the minute anyone with hay fever comes along, even though he be blind and gasping for breath, the entire community stops work and screams with laughter."

The redoubtable Mr. Benchley, whose hay fever was, by his own word, the result of an "old Gypsy's Curse which was laid on the Benchleys generations ago in a dank Welsh cave," nevertheless knew very well that his symptoms - lasting every year from Aug. 18 to Sept. 18 on the dot - had more to do with ragweed pollen. Even back in 1930 when he wrote "A Word About Hay Fever."

He would be gratified to know that although the symptoms - weeply eyes, ruby-red noses and wheezy breathng - are still cause for mirth in some quarters, the medical community, at least, isn't laughing.

It may even be doing something significant for the more than 25 million Americans who suffer from hay fever, asthma or both.

Dr. Richard R. Rosenthal, chief of the allergy section at Fairfax Hospital and an assistant professor of medicine at the Johns Hopkins School of Medicine, says that in the past 15 years, as scientists at last are gaining "more detailed knowledge of the mechanism" of allergies and their control . . . "our knowledge of immunology has absolutely mushroomed."

Dr. Rosenthal conducts clinical tests of new preparations, new methods of diagnosing allergies and ways of controlling them at his offices in Fairfax, Va. He is one of a group of research immunologists - he is of course involved in treatment as well - whose tests, experiments and studies will eventually provide the basis for common medical treatment. Rosenthal's own specialty is in what he calls "inhalation challenges," research and testing involving the breathing process.

To this end, and with the help of electronics specialists at Hopkins, he has devised and and patented a special testing mechanism which responds to the breath of a patient, delivers an amount of antigen or allergen (the thing, such as pollen extract, that causes an allergic reaction such as hay fever) and then delivers an amount of a test medicine, permitting precise cause-effect-relation measurements.

Experiments and testing programs are now underway on promising preparations and techniques. Some, says Dr. Rosenthal, include immunotherapy - a series of desensitizing injections - with preparations in which the "native antigen," say, ragweed pollen, has been changed chemically so that although it gives the patient the necessary immunity, it does not itself have the potential for causing an allergic reaction.

Also, said Rosenthal, there are experiments with products which could reduce the number of injections needed. Researchers are also working on such things as time-release chemicals that could be used in innoculations. They would work along the lined of time-release capsules, releasing a substance into the system in measured amounts at periodic times.

What Rosenthal terms an "important breakthrough" in medicinal control of asthma - now under investigation for its hay fever potential as well - is cromolyn sodium, marketed by the Fisons Corp. as Intal. It was developed about nine years ago by an English scientist who was himself an asthmatic. It has been approved for use in asthma treatment in the U.S. since about 1973 in the form of an inhaled powder, and has produced dramatic relief for some asthma sufferers. It is thought to work, Rosenthal said, by inhibiting the release of histamine, the substance produced in the bodies of alergic subjects in reaction to the allergen.

In some other countries, cromolyn sodium is also available now for use as a nasal spray or in eye drops for allergic symptoms like those induced by hay fever. The FDA currently has these under consideration for licensing here. Some allergists may already be prescribing the drug in severe hay fever cases, or in test situations, but results have not been widely published and, until the drug is approved for hay fever use, it cannot be sold or advertised for that.

Meanwhile, although Benchley's gypsy's curse restricted his allergy to the ragweed season, there are plenty of other things in the air to keep the immune laughing at one poor sufferer or other form just about the first thaw to the first frost. Things like trees, grasses, bushes, flowers. And don't think you can escape just by going to another part of the country. If the oak tree pollen and the Bermuda grass and the ragweed don't get you in the Southeast, the Russian thistle may tickle your nose in the South Dakota, Washington or Oregon, or the salt busy may make your eyes smart in New Mexico or you may sneeze because of amaranth in Arizona. (Nor are those exotic-sounding, but all too mundane plantlife-allergens limited to those states.)

Dr. Dorothy Sogn, of the Immunology, Allergic and Immunologic Diseases Program of the National Institutes of Health, suggests three currently availabe measures for hay fever victims:

Avoidance.There is no ragweed in Europe. But Dr. Sogn concedes the lack of general practicability of a six-week annual European tour. However, she suggests that a victim may create a little haven of relatively pollen-free air in one's own bedroom with daily wet-mopping and dusting combined with an air-filtration unit.

Treatment of symptoms. Antihistamines and decongestants help alleviate symptoms somewhat, sometimes. There are also steroid-containing medications and nasal sprays, as well as a body of broncho-dilators which are usually useful, especially for wheezing - but mainly for short periods. These can have side effects.

Immunothrerapy. This involves buidling up an immunity in a person by injecting measured amounts of the substance to which he or she is senstive over a long course of treatment. After, of course, the guilty allergen is clearly identified by various testing procedures.

Dr. Rosenthal finds a combination of all three recourses in varying degrees is now probably the best approach, but he continues to search for the surefire way to wheezeless, sneezeless seasons. And he is eager to find volunteers to help him. If you are interested in participating in an allergy-research program, he will welcome your call: 573-4440.

. . . And gesundheit!