Acne vulgaris is the medical name for common acne -- the presence of blackheads, whiteheads, and other types of pimples on the skin. The most common spots for breakouts are the face, chest, shoulders, and back. Although mild acne may improve with over-the-counter treatments, more severe forms should be treated by a dermatologist.

If you’ve got a face full of large, red, inflamed blemishes that seem to last for months, chances are you’ve got one type of severe acne: nodules, cysts, or acne conglobata. These are indicative of a deeper condition than your average acne type and can cause more severe and permanent damage to your skin if left untreated. If topical, over-the-counter treatments aren’t clearing these types of blemishes after a few weeks, it’s time to see a dermatologist for stronger, prescription-strength medicine.