Allergens can be a form of acnegenicity. Acnegenicity refers to the ability of a substance to cause a pustule or papule in the skin.
Unlike comedonal acne, the beginning lesion is not a comedone. The trigger is from an irritation or allergen. You can have a completely non comedogenic product yet still get acne. If there are irritants or allergens and you are sensitive to them you can get cystic breakouts. They can occur within 24 hours of use and usually stop after discontinuing the product causing this.