"He wanted to go home right away, but he is being held as a precaution," Klun said.
"I'm fine, I'm fine," the billionaire prime minister later told the ANSA news agency.
A 42-year-old man who had a 10-year history of mental problems, was arrested following the attack, police said.
Scuffles had broken out after about 10 people jeered Berlusconi at the rally of his People of Freedom party, calling him a "clown".
He shouted back; "Shame on you!" and drowned out their heckling with the help of the sound system.
The attack comes at the end of a difficult year for the controversial prime minister.
His popularity recently plummeted after accusations of sexual encounters with escorts, a separation from his wife, the loss of immunity prosecution and the re-start of two corruption trials.
On Friday in Milan, one corruption trial in which Berlusconi is accused was adjourned until January 15.
The prime minister faces allegations that he paid his British former tax lawyer, David Mills, $600,000 to give false evidence in two trials in the 1990s.
Mills, who was tried separately, was sentenced to four-and-a-half years in jail over the case in February.
Earlier this month, about 350,000 Italians called for his resignation in what they dubbed the "No Berlusconi Day".
In 2004, an Italian bricklayer hurled a camera tripod at Berlusconi, injuring him slightly on the head.