Keratosis pilaris

Keratosis pilaris is a common skin condition that causes small, rough bumps on the skin, often described as feeling like sandpaper. It mainly affects the hair follicles on the upper arms, thighs, cheeks, and buttocks. These bumps are caused by a buildup of keratin, a protein that protects the skin, which blocks the hair follicles. The condition involves the skin system and primarily affects the texture and appearance of the skin rather than causing pain or serious health problems. It is often more noticeable in dry or cold weather and can sometimes be associated with other skin conditions like eczema. While it is harmless, it can cause cosmetic concerns for many people.

Keratosis pilaris is a benign follicular hyperkeratosis characterized by the accumulation of keratin plugs within the orifice of hair follicles, leading to the formation of small, rough, follicular papules. The pathophysiology involves abnormal keratinization and retention of keratinocytes, which obstructs the follicular opening. It is commonly seen in children and adolescents and is often associated with a personal or family history of atopic dermatitis or ichthyosis vulgaris. The condition primarily affects the epidermis and hair follicles, with a predilection for the extensor surfaces of the upper arms and thighs. Although the exact genetic basis is unclear, mutations in the filaggrin gene have been implicated in some cases. Clinically, it is significant due to its chronic nature and cosmetic impact, but it does not lead to systemic complications.