A randomized, controlled, double-blind, clinical trial will be conducted to study the evaluate the effect of blue light combined with corticoid treatment in the preoperative and postoperative period of keloid removal surgery.

Keloid scars are characterized by the excessive proliferation of fibroblasts and an imbalance between the production and degradation of collagen, leading to its buildup in the dermis. Although the genesis of this condition is not yet fully clarified, keloids are known to have a genetic component and are related to an increase in the expression of transforming growth factor beta (TGF-β). There is no "gold standard" treatment and recurrence is frequent. Therefore, novel treatment options are needed. In vitro studies have demonstrated that photobiomodulation (PBM) reduces the multiplication velocity and quantity of fibroblasts as well as the expression of TGF-β. This is a low-cost, noninvasive therapy with no side effects that has proved to be a good tool to complement the most established treatment. Therefore, the purpose of this study is to evaluate the effect of blue light combined with corticoid treatment in the preoperative and postoperative period of keloid removal surgery. A randomized, controlled, double-blind, clinical trial will be conducted involving two groups: 1) Sham (N = 29): intralesional administration of corticoid (IAC) and sham PBM in the preoperative and postoperative periods of keloid removal surgery; and 2) active PBM combined with IAC (N = 29) in the preoperative and postoperative periods of keloid removal surgery. Transcutaneous PBM will be performed on the keloid in the preoperative period and on the remaining scar in the postoperative period using blue LED (470 nm, 0,4W, 24J per point on 10 linear points, total 240J). The patients will answer two questionnaires: one for the assessment of quality of life (Qualifibro-UNIFESP) and one for the assessment of satisfaction with the scar (PSAQ). The team of plastic surgeons will answer the Vancouver Scar Scale (VSS). All questionnaires will be administered one, three, six, and twelve months postoperatively. The keloids will be molded in silicone prior to the onset of treatment and prior to excision to assess pre-treatment and post-treatment size. The same will be performed for the remaining scar at one, three, six, and twelve months postoperatively. The removed keloid will be sent for histopathological analysis for the determination of the quantity of fibroblasts, the organization and distribution of collagen (picrosirius staining), and the expression of TGF-β. All data will be submitted to statistical analysis.

Inclusion Criteria:

• Age: 18 to 65 years;
• Fitzpatrick skin phototype I-VI;
• Keloid with no type of previous treatment;
• Recurring keloid after surgical excision;
• Recurring keloid after use of other therapies and at least three months without treatment.

Exclusion Criteria:

• Keloid in treatment;
• Pregnant and lactating women;
• Keloid with primary synthesis of the skin and no possibility of excision.
• Contraindications for undergoing surgery (e.g.: coagulopathies, diabetes myellitus, drug allergies);
• Contraindications for the use of corticosteroids;
• All types of Collagenosis.

The evaluator, analyst, and participants will be unaware of the group to which the participants are allocated. The operator will also be unaware of whether the blue light has a biological effect or is a placebo.