Karen DeYoung, deputy foreign editor of The Washington Post, has won the 1979 Sigma Delta Chi Award for distinguished foreign reporting, based on her reports on the revolution in Nicaragua that brought down the Somoza dictatorship.

"Her reporting showed clarity in a situation difficult to explain, under difficult and dangerous conditions on a significant event . . . She maintained her objectivity and wrote stories that were balanced," said the panel of judges for the national journalism society.

DeYoung, a graduate of the University of Florida at Gainesville, worked for the St. Petersburg Times (Fla.) before joining the Post staff. She has been a correspondent on a variety of Latin American assignments.

The award to DeYoung, which will be presented in ceremonies May 10 at the Park Hilton Hotel, Seattle, was one of 16 presented to journalists for outstanding work in 1979.

Other winners included Miami Herald reporters Gene Miller, Carl Hiaasen, Patrick Malone and William D. Montalbano for a series on medical abuses; Rick Sinding of the Hackensack (N.J.) Record for editorials on the state legislature; Gordon Eliot White of the Salt Lake City Deseret News for stories on radioactive fallout from atomic testing; Eddie Adams of the Associated Press for news photography; John P. Trever of the Albuquerque Journal for editorial cartoons; The Miami Herald for a series on police brutality; Michael Vargo of the Pennsylvania Journal for stories on the Three Mile Island incident; and the National Geographic for an article on nuclear energy.