The cause was complications of a heart attack, said his son, attorney Paul M. Hittelman.
Hittelman was one of 11 Los Angeles physicians questioned by the House Committee on Un-American Activities in October 1952 after a fellow doctor alleged that they were members of a medical unit of the Communist Party. Like the writers and directors of the so-called Hollywood 10, the doctors argued that questions about their political views violated their constitutional rights and refused to answer.
A lifelong progressive, Hittelman believed that he and his colleagues had raised the suspicions of Red hunters because they favored health programs and other benefits for the poor.
"The attitude of the physicians who were called before the committee was one of social activism," he recalled in a 1999 article in The Times. "Most of us worked in clinics. It all goes back to seeing the big gaps in healthcare delivery. We (tried) to liberalize the medical profession. … We got a group together to back Roosevelt, and that was a Red activity."
Hittelman was called before the state Senate Fact-Finding Committee on Un-American Activities, also known as the Burns Committee, as well as the House Committee on Un-American Activities. Although he was not prosecuted, he was blacklisted for several years. For most of the 1950s, he was barred from the staff of Cedars of Lebanon Hospital, a prestigious facility in Hollywood that later merged with Mount Sinai Hospital to form Cedars-Sinai.
According to a transcript of the House committee's hearing on Communist activities in professional groups, Hittelman evaded questions about whether he had ever belonged to the Communist Party, arguing that he had the right under the Constitution to keep his politics private.
"When I first went into medical school, the first day I was presented with a box of bones and a skull and, lo and behold, the skull had a hinge on top and I could unhinge it and look inside," he told the committee. "My skull does not have a hinge on top, and nobody is going to look inside my skull."
His son said he did not know if his father had ever been a Communist, "but he certainly was a left-wing activist" who was involved in groups that fought for workers' rights, racial equality and the expansion of civil liberties.
The son of Russian Jews, Hittelman was born Dec. 25, 1910, in Rochester, N.Y., where his father established a successful business as a painting contractor and builder. In 1920 he moved with his family to Los Angeles and grew up in Boyle Heights. After graduating from Roosevelt High School, he attended UCLA and UC Berkeley, where he earned a bachelor of science degree. He received a medical degree from UC San Francisco in 1936.
During World War II he served stateside and in the Philippines with the U.S. Army Medical Corps.
After he was blacklisted at Cedars, Hittelman continued to see patients privately and at smaller hospitals in the area. He eventually gained staff privileges at Cedars-Sinai, practiced internal medicine in Beverly Hills and volunteered at the Venice Family Clinic. He retired in 1994.
Survivors include his wife, Helen; three sons, Karl of Corte Madera, Calif., Paul of Los Angeles and Jeff of Butte Valley, Calif.; two siblings, Nathan Hittelman and Celia Frimkess, both of Los Angeles; six grandchildren and five great-grandchildren.