Blackheads are a mild form of acne that appear as unsightly, open pores that appear darker than the skin surrounding them. They get their dark appearance from a skin pigment called melanin, which oxidizes and turns black when it's exposed to the air. Blackheads aren't caused by dirt, but by sebum (oil) and dead skin cells blocking the pore. If the pore remains open, it becomes a blackhead; if it's completely blocked and closed, it turns into a whitehead.
Photodynamic therapy is a new acne treatment. It begins with light microdermabrasion. This is used to remove dead skin cells on the face's surface. Then, an acid is put on the skin for 30 to 60 minutes. After this period, the acid is taken off. Lastly, the skin is treated with a laser. This treatment is still being researched, but seems to give positive long-term results.
Drugs: Some medications may cause or worsen acne, such as those containing iodides, bromides, or oral or injected steroids (either the medically prescribed prednisone [Deltasone, Orasone, Prednicen-M, Liquid Pred] or the steroids that bodybuilders or athletes sometimes take). Other drugs that can cause or aggravate acne are anticonvulsant medications and lithium (Eskalith, Lithobid). Most cases of acne, however, are not drug related.