There was the architect whose blueprints blurred from the sweat dripping off his hands. Or the executive who could only wear cotton clothing so he could continually wipe the sweat off his hands. Or the police officer whose uniform, even on the coldest of days, was wringing wet under the arms.

In the machine-tool industry, they are known as "rusters."

But excessive sweating is no joke. Not just a little dampness under the arms, but sweat that literally drips off nervous palms -- puddling on a conference table or keyboard or desk.

"These are desperate individuals," said Dr. Mervyn Elgart, chairman of dermatology at George Washington University Medical Center.

Excessive sweating, or hyperhidrosis, is doubly frustrating because it tends to be self-perpetuating. "You're worried about shaking this guy's hand because your hand might be wet," said Elgart, "so your hand gets wet."

Sweating on the hands, feet and armpits is almost entirely due to emotional stress rather than heat or physical exertion, said Dr. Richard Dobson, chairman of the department of dermatology at the Medical University of South Carolina. A pro football quarterback in a tense game, he pointed out, may need to dry his hands before each play, even in subfreezing weather.

Hyperhidrosis has no known cure, and only a few products claim to offer even temporary relief.

One of them is the Drionic, an electric sweat-control device recently cleared by the Food and Drug Administration after a six-year legal battle. Drionic is approved for use only with a doctor's prescription.

The battery-powered Drionic, which retails for $100, consists of two felt pads set in a plastic tray filled with ordinary tap water. The wet pads are held against the palms or the foot soles or even the armpits for about 20 minutes, conducting a mild electric current through the skin.

The Drionic uses a phenomenon known as iontopheresis, which was discovered in the 1950s and has been used since the 1970s to treat excessive perspiration. For reasons that scientists still don't fully understand, mild electrical stimulation of the sweat ducts in the skin seems to inhibit sweating temporarily without damaging or clogging them.

"The idea is not new," said dermatologist Elgart. "What's new about Drionic is that it's portable and saleable to the patient."

Most patients see progress after about 10 treatments of approximately 20 minutes each, said Robert Tapper, president of General Medical Co., which markets the device. The treatment lasts up to six weeks, he says, after which the series must be repeated.

Has Tapper, a 59-year-old self-described "businessman with a minor engineering background," tried Drionic himself?

"I was numero uno guinea pig on the thing," he said. "But I'm a lousy test subject because I'm dry as hell anyway."

Published studies on Drionic, though "impressive," are not conclusive because they were not scientifically controlled, said South Carolina's Dobson, who is president of the American Academy of Dermatologists. He said his department plans to conduct controlled studies of Drionic next year.

But Dobson said he has used Drionic on patients "and was able to verify its efficacy and safety."

The Drionic is promoted by General Medical in full-page color advertisements with bold red-letter headlines that proclaim: "STOP SWEAT SIX WEEKS!" The ads tout Drionic for workers ("High technology occupations cannot tolerate sweaty hands"), athletes ("The tennis player's game is affected by slippery hands -- also the golfer, bowler, weightlifters, baseball batter, gymnast, etc.") and people concerned about the "social stigma of wetted garments, clammy handshake and possible bromidrosis sweat odor ."

But some dermatologists are less enthusiastic.

"We had an awful time with the study," said Dr. Irwin Freedberg, now chairman of dermatology at New York University Medical Center, who helped test Drionic when he taught at Johns Hopkins Medical School a few years ago. "It was a nothing, not worth pursuing. I've done a lot of studies, and sometimes they bomb. This one was a bomber."

"We tested it at Northwestern University and it just didn't work," said Dr. Fred Levit, a Chicago dermatologist who spoke here at the recent convention of the American Academy of Dermatologists. "It did absolutely nothing. There was no evidence the thing worked at all."

Levit said the side effects Tapper claims to have overcome with Drionic -- such as tingling -- have not been a problem with the competing device he uses in his practice. That device is made by the R.A. Fischer Co.

"I have uncomfortable feelings about Drionic ," Levit said. "Maybe it's going to work. Maybe it's going to be cheaper. But I don't exactly think it's right to claim in a big headline that you can stop sweat for six weeks."

But in an affidavit filed in U.S. District Court here in connection with General Medical's civil suit against FDA, Levit said the Drionic "is substantially similar to the Fischer device" that he has recommended to patients since 1974.

Under the 1976 amendments to the FDA law, new medical devices such as Drionic can be marketed if they're certified as safe and effective by the FDA. Marketers can also obtain FDA approval by showing that the device is "substantially equivalent" to a product marketed before the 1976 amendments took effect.

During a protracted six-year legal battle with FDA, General Medical tried both routes to get Drionic onto the market, said Kathy Schroeher, an FDA attorney. Drionic's legal history at the FDA is one of the most complicated she can remember.

Last October, FDA finally agreed that the Drionic is "substantially equivalent" to Fischer's device and, therefore, should be allowed onto the prescription-only market. Drionic was already being sold in 11 other countries, including Canada, England, France, Israel and Saudi Arabia.

Tapper won't say how many employes his company has. "That I keep quiet," he said. "We're extremely small, I can tell you that. I had 48 at one time, but we're smaller now."

General Medical has a production capacity of 750,000 units a year at its Los Angeles plant, but Tapper said he would be "happy" to reach sales of 250,000 within two years.

Dermatologist Levit expressed concern that Tapper would try to "get everybody with sweaty underarms" to buy the Drionic.

"Hyperhidrosis is not a disease," Levit said. "It's an exaggeration of a normal condition. It's normal for your palms and feet to sweat when you're nervous. It's like having ear lobes. How big do they have to be before it becomes abnormal to have ear lobes?" BB ut Tapper said various estimates put the incidence of hyperhidrosis at 1 perB cent to 5 percent of the population. Either figure, he noted, would mean a huge potential market for Drionic.

"I'll take it," he said with a laugh. "Nice numbers. Write to me on the Riviera."

Until now, General Medical has stayed in business with essentially one product: a hair-remover with a spring-loaded needle, called Perma-tweez.

"We were extremely successful with Perma-tweez, extremely successful, until 1978," noted Tapper, who said the company used up those profits trying to get Drionic onto the market.

"We hope to recoup now, of course."