Acne is of different types. Some of them are non-inflammatory while some are inflammatory. The inflammatory kinds include:
Papules- These are pink, inflamed lesions formed due to the blocking and then rupturing of hair follicles with excess oils, dead skin cells, and acne-causing bacteria.
Pustules- These are advanced kinds of papules that appear as small, red pimples with a white top that is filled with pus and sebum.
Nodules- These are much larger kinds of lesions that develop underneath the skin- usually in the dermis (middle skin layer). They are hard, painful lumps containing excess natural skin oil, dead skin cells, and infection from the ruptured hair follicle which has spread beneath the skin. If they are scratched or rubbed, they can cause acne scars to develop.
Cysts- These are also large skin lesions developing in the skin dermis. They are soft to the touch, swollen, painful, filled with pus, and can cause acne scars.
The non-inflammatory types include:
Open comedones- These have a wide opening consisting of dead skin cells and sebum plugs through which air can easily pass. When air comes in contact with the hair follicles clogged with excess sebum and dead skin cells, their chemical reactions change the hair follicles' color to black, hence these are commonly called blackheads.
Closed comedones- They have a tiny opening, so air is not able to get access to the hair follicles, which means the follicle cannot turn black. Thus this type of acne spots remain white colored, hence they are commonly known as whiteheads.
Acne is most commonly associated with acne vulgari. This type of acne is categorized as mild, moderate, and severe and usually affects teenagers. These categories are used to diagnose acne by dermatologists and other healthcare professionals. However, there are also other less-known types such as acne rosacea, cosmetic acne, and smoker’s acne- depending upon their varying cause.