It is widely suspected that the anaerobic bacterial species Propionibacterium acnes ( P. acnes ) contributes to the development of acne, but its exact role is not well understood.  There are specific sub-strains of P. acnes associated with normal skin, and moderate or severe inflammatory acne.  It is unclear whether these undesirable strains evolve on-site or are acquired, or possibly both depending on the person. These strains have the capability of changing, perpetuating, or adapting to the abnormal cycle of inflammation, oil production, and inadequate sloughing of dead skin cells from acne pores. Infection with the parasitic mite Demodex is associated with the development of acne.   It is unclear whether eradication of the mite improves acne. 
Acne conglobata often starts as "normal acne" with comedones and pustules, and progressively degenerates into nodular cystic lesions, this is because of an overproduction of oils from the sebaceous glands. Often, cysts erupt as painful, oozing lesions on the surface of the skin that can cause disfigurement and scarring. Severe skin inflammation, swelling, pain, and sensitivity are the most common physical symptoms of the disorder. A sufferer may experience significant psychological symptoms as well, such as depression, anxiety, and self-consciousness due to prevalent, disfiguring scars.
The first thing dermatologists often do is determine the type of acne that a patient is suffering from. This helps them develop a treatment plan and avoid products that may be ineffective or exacerbate certain acne types. Less severe forms of acne may be treated at home with over-the-counter products. Acne affects people of all races and skin types and usually begins during the teenage years. This condition can last for many years and must be treated promptly so that it doesn’t worsen. Improper treatment of acne may cause scarring that can become permanent.