Why do some teens get acne while others don't?

There are so many factors involved in acne that it is impossible to really say why one teen gets acne and another who seems to lead a similar life style doesn't. There is some research that suggests the hormones found in dairy products and a western diet in general may be a factor, but there are many others. Hormones, heredity, greasy cosmetics, stress, humid polluted climates, irritation to the skin, chafing, and squeezing pimples all can contribute to acne.