There are several factors which contribute to the development of acne: the overproduction of oil by enlarged oil glands in the skin, blockage of hair follicles that release oil and the growth of bacteria within hair follicles. Other factors which can lead to breakouts include stress, accumulation of dead skin cells, an allergic reaction to bacteria in the pores, scratching, certain medications and using anabolic steroids. Genetics and hormonal changes also play a big role in whether or not you will suffer from acne breakouts.
Types of Acne
Whiteheads
These appear as a white spot on the surface of your skin. They are caused when a pore is completely blocked, trapping in oil (sebum), dead skin cells and bacteria. They usually heal much faster than other types of acne.
Blackheads
These occur when a pore is only partially blocked leaving a portion open to the surface causing the trapped oil, bacteria and dead skin cells that contain skin pigment to drain to the surface of your skin and oxidize, then turning it brown or black in color. A common misconception is that blackheads are caused by dirt. This is untrue, they cannot be washed away. In fact they often take a long time to heal.
Pustules
These are also a very common type of acne (also referred to as a zit). They appear as a red inflamed bump with a white or yellow center. While best practices say you should never squeeze a pustule, if you must then it is a good idea to follow the advice of medical professionals who suggest gently poking the pustule with a sterilized needle and draining the pus with tissue-covered fingers.
Papules
Papules are inflamed red, swollen and often tender bumps that have no head. These occur when there is a break in the follicular wall. White blood cells rush in and the pore becomes inflamed. It is very important not to squeeze a Papule because it will make it worse and even cause scarring.
Nodules
Nodular acne is much larger other forms of acne and can be very painful. They are large, hard bumps under the skin surface. they often cause scarring and impaction which can lead to future flare ups. As with papules, nodules should never be squeezed because you can cause severe trauma to the skin and the lesion may last for months longer than it normally would.
Cysts
These appear similar to a nodule, but they filled with pus. They can be extremely painful and cause scarring as well. Squeezing a cyst may cause an infection and lead to more painful inflammation which will last much longer than if you had left it alone.