EL CAJON, Calif. - A teenager was injured Monday while trying to put out flames spreading through a neighbor's unoccupied trailer home at an East County mobile-home park.

The blaze in the 400 block of Van Houten Avenue in El Cajon was reported about 9:45 a.m., according to Heartland Fire & Rescue.

A 17-year-old area resident who attempted to extinguish the flames before emergency crews arrived suffered a cut arm and was transported Sharp Grossmont Hospital, a dispatcher said. No other injuries were reported.

It took firefighters less than 10 minutes to subdue the blaze, which destroyed the trailer.

The cause of the fire was under investigation.