A scar arises from proliferation of fibrous tissue that replaces previously normal collagen after a wound or ulceration breaches the reticular dermis. Scars have a deeper pink to red color early on before becoming hypo- or hyperpigmented. In most scars, the epidermis is thinned and imparts a wrinkled appearance at the surface. Adnexal structures, such as hair follicles, normally present in the dermis are destroyed. Hypertrophic scars typically take the form of firm papules, plaques, or nodules. Keloid scars are also elevated. Unlike hypertrophic scars , keloids exceed, with web-like extensions, the area of initial wounding. Atrophic scars are thin depressed plaques.
