A face has combination skin if two or more skin types - normal, oily, or dry - are present. One common variation is the T-zone, where chin, nose and forehead skin are oily, while the rest of the face is dry or normal.
Combination skin sometimes causes large pores, blackheads and shiny skin. Oily areas are caused by overactive oil glands, but environmental conditions also contribute to combination skin. Heat and humidity increase oil production, so oily regions are worse in the summer. Cold weather and forced-air heating dry out skin, and oily areas clear up, while normal areas start to flake.
Combination skin often benefits when each section receives site-specific care. For instance, dry parts require moisturizer, while oily zones need a cleanser to reduce oil production.