Enlarged, open pores are a very common concern. Pores are tiny openings on the skin that release sebum or oil secreted by the oil glands to moisturize the skin. Large open pores can make the skin look very uneven. The most common cause of open, large pores is genetically oily skin, in which the oil glands secrete high amounts of oil that is discharged through the pores. However, as we age, the skin loses elasticity and hence the pores may appear large and open even in absence of excessive oil secretion