High Elevation Souffle

There is a fairly detailed answer to this available here.

It appears that the answer depends a little on the type of cookie. If you have a cookie that has a great deal of air in it you'll have the same problem as cakes do. If you are working with a very dense cookie that can't really fall (since there isn't anywhere to go). At that point you're just down to watching baking times and temperatures, which are easier to monitor.

Sugar fermentation occurs more quickly at high altitude so you need to cut back on the time that you're allowing the dough to rise.

Salt controls the action of the yeast so you might be able to increase it slightly since you're talking about pizza crust and not a sweet yeast dough.

Are you using all-purpose flour? If so, try bread flour. The higher gluten content of bread flour typically requires a longer amount of time for rising due to the extra gluten that needs to stretch and expand. Additionally, it will be a stronger dough even when it is expanded.