Acne forms when hair follicle of skin gets plugged by excessive production of oil called Sebum by the Sebaceous Glands and dead cells and get infected by bacteria.

From sporadic whiteheads to large pus-filled cysts, acne has many types. These may be either interconnected or utterly independent in their genesis.

Acne types are divided into two basic groups.

'Inflammatory Acne
'Non-inflammatory Acne

Inflammatory Acne:

This basic group of acne types is consisted of inflamed comedones that are caused by bacteria in blocked follicles. Inflammatory acne includes:

Acne Conglobata: The back, buttock and chest acne. It is rare, but serious.

Pustule: The small round acne that contains pus. Mostly, it appears yellow or white at center and red at the base.

Cysts: Pretty similar to nodule with the difference of high possibility of acne scarring.

Papule: The mildest acne, which appears on the skin as small, but firm pink bump.

Nodule: The very large and painful pus-filled acne firmed deep within the skin. It can cause scarring.

Non-inflammatory Acne:

It is consisted of two types of blocked pores. It includes:

Whitehead (Closed Comedo): As the name suggests, it appears on the skin as whitish bumps. It appears because the blocked follicle remains under the skin.

Blackhead (Open Comedo): The cause of its dark color is mistaken with dirt. In fact it is the buildup of melanin that gives it dark color. It appears because the blocked follicle enlarges and pushes through the surface of the skin.