The fight occurred about 5:10 p.m. in the 13700 block of Sherman Way, near Woodman Avenue, in Van Nuys, according to the Los Angeles Police Department.
The pit bull appeared to be protecting its master when it bit the victim, who was taken to a hospital, according to Officer Drake Madison of the Los Angeles Police Department's Media Relations Section.
The victim's condition was not immediately available.
The dog was seized because it was deemed to be vicious, Madison said.
Neither man was arrested.