Acne is a result of inflammation and/ or an infection of the sebaceous glands of hair follicles. These glands lie under the surface of the skin and are attached to hair follicles which open to tiny pores on the skins surface. The sebaceous glands produce oil (sebum) and are responsible for keeping the skin and hair soft and supple.
When the pores become blocked, comedone (whiteheads/blackheads) are seen and if sebum clogs up the pores, spots result and are seen as pimples or pustules. The blocked pore may become infected with the otherwise harmless skin bacteria, C. acnes. This may initiate an immune response leading to inflammation and redness in the surrounding area. The end result being larger spots that are pus filled which may go on to develop into nodules and cysts.