Scarring typically occurs after trauma, burn injury or surgery. Hypertrophic scars (scars with excessive amounts of a protein called collagen) and keloids (hypertrophic scars that grow beyond the boundaries of the original wound) are types of abnormal scarring that are termed "dermal fibroproliferative disorders" - disorders of abnormal growth of fibrous tissue in the dermis, a layer in normal skin. These disorders present as raised, red and itchy lesions which variably respond to various treatment modalities, such as corticosteroids, pressure garments, laser therapy, the use of silicone sheets and radiotherapy. Surgical excision of hypertrophic scars or keloids often leads to recurrence resulting in cosmetic deformities and contractures.