What is the primary cause of keratosis pilaris, a condition featuring small bumps on the skin?

Keratosis pilaris is primarily caused by a buildup of keratin, a protein that protects the skin from harmful substances and infection. This keratin forms hard plugs within hair follicles, leading to the characteristic small, rough bumps found on the skin's surface, often on the upper arms, thighs, and cheeks. This condition is generally harmless and commonly occurs in individuals with dry skin or other skin conditions that affect keratin production and shedding.

While factors such as excess sebum production, bacterial infections, or allergic reactions may affect the skin, they do not directly lead to the formation of keratosis pilaris. The pivotal role of keratin buildup distinguishes this condition from other skin problems related to oiliness, infection, or hypersensitivity.