- Whitehead – is a plugged sebaceous gland with an opening that is not widely dilated. Whiteheads begin to bulge because the sebum produced cannot escape. They are generally soft,lack inflammation,and are easy to extract.
- Backhead – is an open follicle with a black surface plug, which has been oxidized and discolored due to sebum’s contact with the air.
- Papules – Is a small elevation of the skin, usually inflammatory, that does not contain pus. Papules are similar to vesicles in size, and if they progress they can become pustules.
- Cyst- Is an abnormal membranous sac containing a gaseous, liquid or semi-solid substance.
- Nodule- or Tumor is a solid mass within the skin. It may be soft or hard,fixed or freely moving.
- Pustule – is a small inflamed elevation,the next step in the progression from a papule,filled with bacterial fluid and pus. Pustules appears red and cloudy or white.