Mechanistic Basis of Ablative Carbon Dioxide Laser in Treating Hypertrophic Scars

- Adult patients aged ≥ 16years

- Patient with hypertrophic scarring as a result of deep dermal or full thickness burns/trauma.

- Trauma or Burn sustained more than 12 months prior to recruitment.

- Treatment area to be ≥25cm2 confluent scarring with a comparable control scar on limb or trunk General Exclusion Criteria:

- Patients under 16 years of age

- Previous laser therapy treatment to the study site

- The use of recent (within 6 months) or concurrent invasive scar treatments, including intra-lesional pharmaceuticals, micro needling or other laser modalities (e.g. Pulse-dye.)

- Known allergy or contraindication to EMLA™ 5% Cream (Lidocaine 2.5% and Prilocaine 2.5%), Dermol 500TM (Benzalkonium Chloride 0.1%; Chlorhexidine Dihydrochloride 0.1%; Liquid Paraffin 2.5%; Isopropyl Myristate 2.5%) or 50:50 ointment (White Soft Paraffin Liquid Paraffin %w/w 50 50.)

- Patients with Fitzpatrick skin type of 5-6 due to nature of the skin Laser Treatment Exclusion Criteria

- The presence of acute infection at the proposed treatment site

- Pregnancy or lactation

- Patients with poorly controlled Diabetes mellitus HbA1C >9% or 75mmol/mol within last 3 months)

- Patients experiencing acute exacerbation of Chronic skin diseases e.g. psoriasis or eczema

- Immunosuppression (HIV, drugs with immunosuppressive effect)

- Use of Roaccutane at any time within the last 6 months

- Autoimmune disorders in active stage (for example: 1. Localised; Type 1 Diabetes Mellitus, Addison's, Grave's and Crohn's Disease, 2. Systemic; Rheumatoid Arthritis, Multiple Sclerosis, Lups and Scleroderma).

- Known history of keloid scarring