It was "further alleged that this is an aggravated breach, as defined in FA Rule E3[2], in that it included a reference to ethnic origin and/or race and/or religion or belief".
Anelka made the gesture, a Nazi-style salute, during a Premier League on December 28. He claimed at the time that it was a tribute to his friend, the antisemitic French comedian Dieudonne M'balla.
Reports in the Daily Mail on Wednesday suggested West Brom would refuse to pay for Anelka's lawyer if he chose to contest the FA charge.
If his challenge is lost, the striker faces the prospect of the minimum five game ban being increased, possibly to 10 or more games.