Typical teenage acne, so-called acne vulgaris, is characterized by three types of lesions: the comedo or blackhead; the inflammatory papule; and the pustule or pimple. Drug induced-acne can be difficult to distinguish from other sorts of acne except for the fact that it was not present prior to taking the drug. Machinists exposed to insoluble cutting oils can develop comedones at the sites of exposure. Inflammatory lesions may be less prominent. Acne can also be a part of certain hormonal problems caused by the overproduction of androgens.