Problems with enlarged and/or clogged pores are mainly due to an imbalance in the skin’s sebum production. Oily skin often has distended pores because it produces more sebum. This sebum production is controlled by hormones and increased production may be a result of a hormonal imbalance, such as at puberty or menopause. Men generally have higher sebum production and more widened pores than women, due to higher testosterone levels.
Pores can also appear larger because the skin has lost its elasticity, often as a result of increasing age, smoking or free radicals. A lot of exposure to sunlight affects the size of the pores. UV rays break down the skin's building blocks, collagen and elastin, making the skin and pores less elastic. This then means that they do not contract back to normal as easily, and at the same time become distended more easily.