Milk doesn't necessarily cause acne, but can contribute to it in those that are prone to acne. It tends to be the first question asked depending on the type of acne.
Milk contains a protein called Casein that causes similar effects as gluten. These cause inflammation in the body. Plus many people can’t digest them. Not to mention the amount of hormones that are in regular milk. If your acne is hormonal to begin with this doesn‘t help at all. It also seems many people that drink milk and have acne, tend to drink milk very often. There are various flora and bacteria in the body and an overgrowth will show up on the skin as inflammation or bacterial.
Milk contains a protein called Casein that causes similar effects as gluten. These cause inflammation in the body. Plus many people can’t digest them. Not to mention the amount of hormones that are in regular milk. If your acne is hormonal to begin with this doesn‘t help at all. It also seems many people that drink milk and have acne, tend to drink milk very often. There are various flora and bacteria in the body and an overgrowth will show up on the skin as inflammation or bacterial.
Not all acne is created equal. So it may not be from what you are ingesting, but from what your not ingesting. For example green foods, and other vegetables plus water. If your acne shows signs that it may be caused by something you are ingesting, it would help to test your skin and do a temporary switch. Some alternate options are Almond Milk - I prefer Blue Diamond, unsweetened vanilla or Rice Milk. There are a few others I have never tried like Hemp and Hazelnut. See your professional there are usually signs and symptoms that show that will trigger them asking "Do you drink milk often?"