The only way vitamin D can really cause acne is by virtue of the fact that it is present in a number of dietary items such as milk and eggs that have been found to spark the condition among large statistical groups. In other words, by itself, vitamin D does not cause acne for the masses. But if too many vitamin D heavy foods are consumed on a daily basis and that particular person is sensitive skin-wise to these food groups, complexion trouble may ensue.
Another possible vitamin D related cause of acne is the idea of sunscreen products clogging up the screen pores. Or even just too much exposure to the sun itself. But again, the jury is still out in this realm with regards to definitive scientific data. In fact, some findings even suggest that sun-like nature's true acne elixir, salt water-can help reduce rather than inflame an acne condition.
Vitamin D Overdose
Overall, there is no indication that too much vitamin D causes acne. The conditions generally associated with this type of imbalance are anorexia, heart irregularities, weight loss, and more. And it also does not come from excessive sun exposure.
Since sustained heat on human skin is thought to photo-degrade vitamin D in its nascent and final forms, it's almost impossible to get too much of the sunny ingredient this way. A person only usually overdoses on vitamin D when seriously training as a bodybuilder or other muscle-building athlete, taking supplements on a daily basis to feed their physique.