The mechanism of keloid and proliferative scar formation is still unknown and is known to be related to various factors such as trauma, burns, surgery, infection, foreign bodies, local collagen metabolic disorders, genetics and local immune function. Although there are many types and methods of scar treatment, the results are not very satisfactory.
Surgical treatment Surgical excision of K alone can have a recurrence rate as high as 55.0%, nevertheless, surgery is still the main method of treatment for K and HS at present. Especially in large hyperplastic scars with dysfunction or morphological changes, the scar needs to be excised, fully released and the deformity corrected. After excision of small HS, direct suturing is possible with little skin tension, and skin slice or flap grafting is feasible after excision of large HS.
Compression therapy Successful compression therapy should have a pressure of at least 24 mm Hg. Patients with severe disease must be adhered to with an elastic dressing for a minimum of 4-6 months or longer. Discontinuation time should not exceed 30 minutes per day.
The mechanism of compression therapy may be histologically related to the realignment of the structure of the collagen bundles of the burn scar. Pressurization changes them from a spiral, irregular arrangement to a more regular, linear arrangement with increased gaps and a decrease in the number of cells. It may also be related to the production of hypoxia, where the addition of pressure causes complete occlusion of the adjacent blood vessels, resulting in reduced metabolic activity, decreased partial pressure of oxygen, and reduced extracellular matrix fluids and mediators. Although compression therapy is effective, it is only suitable for large and immature keloids and is not effective for active keloids.
Silicone film dressing Patients with K and HS generally show a significant reduction in clinical symptoms after 2 months of silicone film application, with less itching, less pain, and increased flexibility of the scar. Silicone films are easy to obtain, non-invasive and painless, without side effects, and are especially suitable for children and patients who cannot tolerate and cannot be treated by other methods. The mechanism of silicone film action may be related to hydration, where the hydrocolloid increases the moisture in the surrounding environment. However, this method is only effective in areas where pressure is maintained, such as the extremities.
Medication Corticosteroids Corticosteroids have been used to treat HS and K for decades. The combination of corticosteroid injections alone or (and) surgery is the most popular and effective method of treating K. Steroids alone must be injected directly into K. The effective concentration range is 2.5 to 40 mg/mL. Another method is the injection of debrisone at the wound margin after K excision. This can be repeated for several months if needed. The mechanism of action of deferiprone is not fully understood. Excessive concentrations of steroids can cause side effects. Common ones include local atrophy, delayed healing, tissue necrosis, local ulcer formation and capillary dilation, which are reversible. In individuals with darker skin, irreversible local pigmentation loss can also occur.
To date, for the treatment of HS, surgery has been clinically proven to be the most effective treatment, and postoperative compression with an elastic bandage can prevent scar growth. As for the treatment of keloid, there is still no ideal method. At present, scholars at home and abroad tend to prefer pharmacotherapy, and effective or complete control of keloid proliferation can only be solved by continuous in-depth research with the understanding and mastery of scar mechanism and elimination of the influence of fibroblast proliferation during the wound healing process.