The number of early infectious syphilis cases rose dramatically in Maryland this year, and state health officials said 1987 may be the worst year for the sexually transmitted disease since 1980.

In the first six months of this year, the state has reported 292 cases, compared to 206 during the same period in 1986. Most of the new cases are in the Baltimore area, said Dr. Ebenezer Israel, chief of the state's division of communicable diseases and epidemiology.

Federal health officials reported last week a 23 percent increase in syphilis cases in the United States this year, 8,274 cases compared to 6,725 cases in 1986. They suggested that "with an explosion of interest and work with AIDS, perhaps less attention has been paid to syphilis" and its prevention.

The state's new surge of syphilis, which if left untreated can result in paralysis, brain damage and heart complications, first became apparent last year when a total of 451 cases were reported to the state, 127 more than in 1985.

According to Israel, a breakdown of the state's 1987 figures, excluding the city, indicates that most of the cases were among heterosexuals and that more men than women are contracting the disease.