Cheese is among the many milk products that could lead to acne. Since dairy products are healthy, experts would advise on low-fat dairy products to reduce the negative effects of milk.
Milk contains the hormone IGF-1. This makes calves grow faster but leads to pimple breakout and inflammation in humans.
Combine this with the fact that dairy products increase your sebum levels, spike insulin levels and glue together dead skin cells inside the pores and you get a recipe for disaster. The rate at which this happens varies from person to person. This is why some people are milk intolerant, and others seem to do just fine with it.