It is typical for combination skin to show symptoms of dry skin and those of oily skin in different areas. In most cases, the forehead, nose and chin (called the T-zone) are shiny, oily and possibly even blemished, while the cheeks are dry, dull and flaky. The T-zone is often prone to seborrhoea, i.e. an overproduction of sebum. However, insufficient levels of sebum are produced on the cheeks and sometimes around the eyes.
Factors that can lead to combination skin include hormones, stress, diet or the wrong skin care. In that case, you create the dry or oily parts yourself. Skin care products that are too harsh or aggressive can dry out some facial areas while boosting oil production in other areas at the same time.
Combination skin needs moisture and it may make sense to apply various products to the individual zones.