Chemical Peel and the Pathology Behind It
In simple words, chemical peeling or chemical rejuvenation is a procedure where a chemical agent or combination of agents of defined strength have applied to the skin causing controlled destruction of layers of the skin. This is followed by regeneration and remodelling leading to improvement of texture and surface abnormalities. It is a safe, effective and affordable option for improving skin ageing and imperfection.
Skin is considered the largest organ of the body and has many different functions. The skin is divided in two main regions, the epidermis and the dermis. The dermis is attached to an underlying hypodermis also called subcutaneous connective tissue.
Epidermis – It is the most superficial layer of the skin. The first barrier of protection from the invasion of foreign substances. The epidermis is divided into four layers – stratum corneum, stratum granulosum, stratum spinosum and stratum basalis(basal layer).
Dermis – It is composed of fibroblasts which are responsible for secreting collagen, elastin and ground substance that gives support and elasticity to skin. It supplies the epidermis with nutrients and has its role in thermoregulation. The dermis is subdivided into two zones, upper papillary and lower reticular layer.
Classification of peels according to histological depth
Very superficial peel – Exfoliation of the stratum cormeum, without any epidermal necrosis.
Superficial peel – Destruction of the full epidermis, up to the basal layer
Medium peel – Destruction of the epidermis, papillary dermis and upto the upper one third of the reticular dermis.
Deep peel – Necrosis of the entire epidermis and papillary dermis with inflammation extending to the mid reticular dermis.
The reason behind chemical peeling:
The wound healing process is an important reason for rejuvenation. The phases of wound healing after chemical exfoliation are apparent:
Inflammatory phase (1-5 days) – This phase is evident after peeling as erythema and swelling on the skin.
Proliferative phase (2-21 days) – In superficial peels, the basement membrane is intact, hence normal epidermis is restored in 2 to 3 days. In medium to deep peels, wound is below basement membrane and re-epithelialization takes time.
Remodeling phase (3 weeks to 2 years) – collagen remodeling is the main reason that chemical peels cause rejuvenation and reduce wrinkles.
Benefits of chemical peels:
- The skin becomes noticeably smoother and rejuvenated.
- It reduces pigmentation, improves dull and uneven skin tone, reduces signs of photoagaeing, acne and enlarged pores.
- Removes dead and damaged skin cells and improves skin texture
- Helps in the removal of tan
- Skin becomes brighter and more vivid because chemical peels not only cause re-epithelialization of the epidermis but also collagen remodelling.
Take home message:
Chemical peeling is a simple office procedure for the treatment of acne, pigmentation, skin rejuvenation and photoageing. These are not one time procedures but require 6-8 sessions and maintenance peels to achieve maximum improvement and prevent recurrences. The newer peels are safer and effective.