Which of the following is not considered a skin type?

Oily-dry skin is not recognized as a distinct skin type within the established classifications of skin types. The primary skin types include dry, normal, oily, and combination skin.

Dry skin is characterized by a lack of moisture, leading to flakiness and irritation. Normal skin maintains a balance of moisture and oil, exhibiting few imperfections. Oily skin, on the other hand, produces excess sebum, which can contribute to acne and a shiny appearance. Combination skin features characteristics of two or more types, typically oily in the T-zone (forehead, nose, chin) while the cheeks may remain dry or normal.

The term oily-dry skin may imply characteristics of both oily and dry skin; however, in skincare, skin types are generally categorized into distinct and well-defined classifications rather than combinations that could confuse treatment approaches. Therefore, oily-dry skin does not belong to the conventional classifications of skin types.