The study includes two study groups, one involves treatment with auto-cross-linked Hyaluronic acid by intralesional and hypodermic injection, repeated after two weeks (T14), while the control arm provides an equal treatment but with isotonic saline solution.

Enrolled patients will be randomized into 2 groups with an allocation of 2:1 in study treatment arm and control arm respectively. They will be evaluated using the POSAS scale before the treatment and re-evaluated at 30, 90 and 180 days after treatment.

The scar evaluation will be completed by an ultrasound assessment at time 0 (T0), 30 (T30), T90 and T180 and the DLQI (Dermatology Life Quality Index) to be assessed at time 0 (T0), 30 (T30), 90 (T90) and 180 (T180).

In subjects that will consent, a small surgical biopsy for an explorative evaluation of the scar tissue will be performed before (T0) and after treatment (T30) for a histological assessment.

Inclusion Criteria:

• Signed written informed consent
• Male or female subjects aged ≥ 18 and ≤ 85 years
• Subjects with hypertrophic scars caused by trauma, burn or iatrogenic injury with or without involvement of the mobile joints
• Scar > 2 to < 25 cm2 of surface
• Scar not previously treated with corticosteroids, laser or other invasive treatments
• Scar present for at least 12 months
• Scar located in all areas of the body with the exception of the face and neck
• Fitzpatrick skin score of I-VI
• Subjects willing to comply with all the steps of treatment and follow-up visits
• Subjects willing to refrain from any cosmetic intervention in the area to be treated during the clinical investigation
• Female of child-bearing potential (i.e. not in menopausal status from at least one year or permanently sterilized) must have a negative urine pregnancy test prior the first treatment

Exclusion Criteria:

Subjects with type I and type II diabetes mellitus

• Subjects with oncological diseases in progress or in remission
• Subjects receiving immunosuppressive drugs and corticosteroids, anticoagulants, antiplatelet agents
• Subjects with autoimmune diseases including connectivitis
• Subjects with congenital or acquired immunodeficiencies (including metabolic ones)
• Subjects with known allergy or hypersensitivity to hyaluronic acid or its derivatives
• Participation in clinical trials/investigations in the last 30 days
• Pregnant or breastfeeding women
• If female and of child-bearing potential, subject not using a highly effective method of birth control and not willing to use it during the participation to the clinical investigation
• Subjects not willing to avoid tanning during the clinical investigation
• Subjects with inflammations of the skin, including rosacea
• Subject with skin infection in the area to be treated
• Subjects having a high probability of non-compliance with the study procedures according to Investigator's judgement