Skin Healing – How does it happen?

The Skin Healing Process

Wound healing is an intricate process where the skin repairs itself after injury. In normal skin, the epidermis and dermis exist in a steady-state equilibrium, forming a protective barrier against the external environment. Once the protective barrier is broken, the process of wound healing is immediately set in motion.

The classic model of wound healing is divided into three or four sequential, yet overlapping, phases:

• Hemostasis
• Inflammation
• Proliferation
• Remodeling

Upon injury to the skin, a set of complex biochemical events takes place in a closely orchestrated way to repair the damage.

Hemostasis

• The first stage of healing
• Platelets adhere to blood vessels
• Platelets secrete a substance that helps vessels to vasoconstrict.
• The coagulation cascade forms a clot, stopping active bleeding.

Inflammation Phase

• This is the second stage of healing
• Recognised by redness, swelling, warmth and potentially pain.
• Causes blood vessels to secrete neutrophils into the surrounding tissue.
• Bacteria and debris removed by white blood cells.
  
• Platelet-derived growth factors are released into the wound, causing the migration and division of cells.

Proliferative Phase

• Also known as the granulation stage, starts about four days after wounding.
• Characterized by angiogenesis, collagen deposition, granulation tissue formation, epithelialization, and wound contraction. 
• Epithelialization is an essential component of wound healing.
• Vascular endothelial cells form new blood vessels.
• Fibroblasts secrete collagen and stimulate dermal regeneration.
• Epithelial cells (keratinocytes) proliferate and ‘crawl’ atop the wound bed.
• During wound contraction, myofibroblasts decrease the size of the wound by gripping the wound edges and contracting

Remodeling and Maturation Phase

• Fibroblasts are the main cells involved in remodeling.
• This can take up to 2 years after the initial wound happens.
• This is a fragile process, susceptible to interruption or failure leading to the formation of non-healing chronic wounds.
• Factors that contribute to non-healing chronic wounds are diabetes, venous or arterial disease, infection, and metabolic deficiencies of old age.

Keywords

• Platelets – also called thrombocytes, are blood cells whose function is to stop bleeding
• Aggregated – Platelets join together
• Vasoconstrict – tightening/constriction of blood vessels
• Coagulation (clotting) – the process by which blood changes from a liquid to a gel.
• Fibrin – a protein involved in the clotting of blood.
• Neutrophils – phagocytes – engulf bacteria /debris.
  
• Platelet-derived growth factors – one of the numerous growth factors, or proteins that regulate cell growth and division.
  
• Angiogenesis – growth of blood vessels.
  
• Granulation tissue – new connective tissue.
  
• Epithelialization – an essential component of wound healing, defining a closed wound.
  
• Endothelium – the thin layer of simple cells that lines the interior surface of blood vessels.
  
• Fibroblasts – Secrete collagen and stimulate dermal regeneration.
  
• Fibronectin – binds extracellular matrix components such as collagen and fibrin.
• Epithelial cells – one of the four basic types of animal tissue.
  
• Keratinocytes – the predominant cell type in the epidermis, constituting 90% of the cells found there.
  
• Myofibroblasts – a cell that is in between a fibroblast and a smooth muscle cell in differentiation.
  
• Apoptosis – the process of programmed cell death.
• Biochemical events lead to characteristic cell changes and death.

Why is it important for us to understand skin healing in the beauty industry?

With the advanced nature of beauty treatments in today’s industry it is important to understand the basic principles of skin healing to sully understand the impact we are having on the skin. Whether this be through laser and IPL treatments, or creating physical wounds using skin needling devices. The more knowledge we have on skin healing the more effectively we are able to treat our clients, and maximise the results of the treatments. As well as understanding when a treatment is enough for a client, to not create long term damage to the skin.

So how is skin healing effected by different treatments?

Laser/IPL skin rejuvenation – Light is emitted from the machine and transfers into heat energy in the skin, this in turn stimulates a skin healing response. Therefore, fibroblasts stimulates collagen and elastin production.

Skin Needling – creates tiny micro wounds around 1mm – 1.5mm deep in the skins surface. This therefore creates a skin healing response and collagen & elastin is produced.

Chemical Peel – the product penetrates to the dermis to initiate a skin healing response to produce collagen and elastin and increase support to the dermal matrix . As well as working by fast exfoliating the surface of the skin and increasing cellular turn over.

Plasma Fibroblast Therapy – plasma is electrically charged gas, which essentially creates a mini lightening bolt against the skin. This cauterises the skins surface, and creates an instant tightening effect. As the skins surface is being superficially wounded, it triggers a skin healing response and produces collagen and elastin.