Pigmentation and freckles are patches of skin that advance to a darker colour generating an uneven skin tone. Hyper-pigmentation is the excessive change in pigmentation in the skin.
Sometimes Hyperpigmentation can occur, particularly associated with darker skin types, known as Post Inflammatory Hyperpigmentation (PIH). This condition may be evidenced where inflammation has occurred in the cutaneous skin, for example following acne spots/lesions. It is caused by an overproduction of melanin or irregular distribution of pigmentation.