A pimple occurs when the sebaceous gland, an oil secreting gland, continues to produce oil but cannot expel it as the opening of the gland near the surface of the skin is blocked. Over time bacteria grow in the retained oil and resulting in the red, swollen inflamed lesion.

To simplify it we may break it down into two categories; first, factors that may overstimulate oil production, and second, factors that block the oil release.

Overstimulation of the sebaceous gland may be a part of a natural process such as in teenage due to androgen surge, medical conditions like polycystic ovarian syndrome, medications like lithium, phenytoin, corticosteroid, etc. Nevertheless, stress can also trigger acne, that’s why students experience flares during board exams, or before any important event such as a wedding.

Factors that block the oil release are an accumulation of dead cells, the buildup of skin and hair care products, friction from masks, and tight clothing.