A pimple is a small pustule or papule. Pimples are small skin lesions or inflammations of the skin - they develop when sebaceous glands (oil glands) become clogged and infected, leading to swollen, red lesions filled with pus.
Pimples are also known as spots or zits
The development of pimples is primarily connected to oil production, dead skin cells, clogged pores and bacteria (although yeast infection can also cause pimples to develop).
Sebaceous glands, which are located at the base of hair follicles, can become overactive due to hormone dysregulation, which is whyacne is most commonly associated withpuberty, and why breakouts occur around the time of menses.
The most likely parts of the body to be affected by pimples are the face, back, chest and shoulders due to the proliferation of sebaceous glands in these areas of skin. Pimples are a sign of acne, especially when a breakout occurs.
A diagram of the sebaceous glands (image by openstax college)
The sebaceous glands are tiny skin glands which secrete sebum - a waxy/oily substance - to lubricate the skin and hair of mammals, including humans.
Sebaceous glands are found all over human skin with the exceptions of the palms and soles. There is a greater concentration of sebaceous glands on the face and scalp. At the rim of the eyelids, meibomian or tarsal glands are a special kind of sebaceous gland that secrete meibum, a special type of sebum that helps maintain the eye's tear-film by preventing evaporation.
Several medical conditions are linked to an abnormality in sebaceous gland function, including:
Sebaceous cysts - closed sacs or cysts below the surface of the skin.
Hyperplasia - the sebaceous glands become enlarged, producing yellow, shiny bumps on the face.
Sebaceous adenoma - a slow-growing tumor (benign, non-cancerous) usually presenting as a pink, flesh-colored, or yellow papule or nodule.
Sebaceous gland carcinoma - an aggressive (cancerous) and uncommon skin tumor.
Causes of pimples / zits
The sebaceous glands, which produce sebum, exist inside the pores of our skin. The outer layers of our skin are being shed continuously.
Sometimes, dead skin cells are left behind and get stuck together by the sticky sebum, causing a blockage in the pore.
Pore blockage is more likely to occur during puberty (the process of physical changes by which a child becomes an adult capable of reproduction) as the sebaceous glands produce more sebum at this time.
Where sebum and dead skin cells accumulate and block a pore, this encourages the growth of undesirable bacteria, includingpropionibacterium acnes - the slow-growing bacterium linked to acne.
Propionibacterium acnes generally exists harmlessly on our skin; however, when the conditions are right, it can reproduce more rapidly and become a problem. The bacterium feeds off the sebum and produces a substance that causes an immune response, leading to skin inflammation and spots.
Researchers at the washington university school of medicine identified two unique strains of p. Acnes in the skin of 20% of people with pimples, while those with healthy skin tended not to harbor these strains. The situation was reversed for another strain of p. Acnes: those with pimples tended not to harbor this strain, but it was present in healthy skin. As such, it seems that particular types of bacteria determine the severity and frequency of pimples.