There's two considerations. One is the fixture rating. An LED will certainly meet that because it is much lower power. The other is the temperature of the LED bulb. They rely on convection and radiation to cool. LEDs are far more efficient than incandescents but still only about 35% efficient. The other 65% is dissipated as heat. Many LEDs will overheat in an enclosed fixture.

Can an LED be used in an enclosed fixture? Yes, but only some brands. The issue is the amount of heat that can build up in the enclosed fixture. LED bulbs are very sensitive to heat; if the air in the enclosed fixture becomes too hot, it will shorten the life of the bulb.