Pigment

Hyperpigmentation refers to the skin becoming darker in color than the surrounding skin. Sun and heat are the most common factors that affect hyperpigmentation. Birth control pills, pregnancy, chicken pox, and other trauma to the skin can cause hyperpigmentation. Melasma is a form of hyperpigmentation that is caused by hormones, mainly in women. Hypopigmentation refers to skin that has no melanin. Melanin is the pigment that gives skin and hair color. The more melanin you have, the darker your skin. Demarcation causes skin to appear uneven, usually from picking or scratching.