Scar blackening is considered to be caused by localized hyperpigmentation, scar hyperplasia, scar crusting and so on.
1. Local hyperpigmentation: in the healing process of skin injury accompanied by inflammatory reaction process, most of the scar healing will leave inflammatory hyperpigmentation; if the healing process of improper care leading to local bleeding, infection and other delayed healing factors, it will aggravate the local hyperpigmentation. Most of the visual darkening of the scar is due to this reason.
2. Trauma: poor skin elasticity in the scar area, inappropriate scratching, friction will more easily lead to skin damage, bleeding and scabbing at the injury, visual black; or impact and other mechanical injuries caused by subcutaneous hemorrhage, subcutaneous hematoma, and so on, there will be a black phenomenon.
Scar blackening may also be caused by other reasons, it is recommended to go to the regular hospital, clear diagnosis and symptomatic treatment.