What Causes Open Comedones?

Open comedones (blackheads): Hair follicles become obstructed by keratinized material and sebum, yet the follicular orifice remains open to the external environment, forming open comedones. Because they appear on the skin surface as large or small dark spots, they are commonly referred to as “blackheads.” Their hallmark feature is darkened, visibly enlarged pores; when squeezed, a worm-like plug—darkened at its tip—emerges. These lesions predominantly occur on the forehead, chest, back, and face. The obstruction consists of a keratinous plug composed mainly of sebum, desquamated epithelial cells, and bacteria. The portion of the plug exposed to air becomes darkened due to dust, dirt, and oxidation. Contributing factors include irregular lifestyle habits and endocrine imbalances. Patients are advised to maintain a light, bland diet in daily life and avoid spicy foods.