What is retinoic acid? What about glycolic acid?
Retinoic acid or tretinoin is a retinoid, a derivative of vitamin A. It performs several actions on the skin:
· Thinning of the outermost layer (stratum corneum).
· Keratolysis and exfoliation (peeling: decreases the cohesion of epidermal cells so that they detach).
· Decreased sebum formation by the sebaceous glands.
· Increases follicular epithelial cell turnover (causes spontaneous extrusion of comedones).
· Reduction of finer wrinkles (increases collagen and acid synthesis
hyaluronic).
· Decrease in solar lentigines (“age spots”) due to melanin dispersion.
· Reversal of cellular atypia (anticancer action).
On the other hand, glycolic acid acts mainly by reducing the cohesion of epidermal cells, causing a peeling. At the dermal level, it seems to be able to increase the synthesis of collagen and glycosaminoglycans such as hyaluronic acid.
Why can combining both substances be beneficial in the treatment of acne scars?
Acne marks are mostly secondary to dermal atrophy due to collagen loss. All those active ingredients that are capable of inducing the formation of collagen and hyaluronic acid will progressively improve the scars (the effect is perceived after 3 – 6 months of use). In some studies it has been shown that the desquamation of the upper layers of the skin (stratum corneum) by salicylic acid increases collagen synthesis. This action is also assumed to be applied to tretinoin and glycolic acid. Because non-ablative lasers do NOT act on the epidermis, the combination of a topical preparation containing these components will enhance the effect exerted on dermal neocollagenogenesis .
What is the effectiveness of a topical combination of retinoic and glycolic acid for acne scars?
According to the study by Chandrashekar et al., in which patients with acne scars were treated only with a combination of tretinoin 0.025% plus glycolic acid 12% over a period of 3 months, up to 91% of the subjects experienced improvement to some degree and 43% achieved “good or very good” improvements on the Goodman & Baron scale (assesses spots, atrophic, hypertrophic or keloid scars). Up to 86% of patients experienced a marked improvement in acne spots.
What are the adverse effects of a low-concentration combination of tretinoin and glycolic acid?
The main one – although not constant – is skin irritation (erythema, flaking), which is typical of any peeling. In fact, it is thanks to this renewal of the upper layers of the skin that acne marks improve. It is possible that the first weeks, if you still suffer from active acne, it may worsen slightly, as the comedones (pimples) externalize and can become inflamed. This rebound effect is mild and temporary: the treatment should not be suspended, but quite the opposite.
While using these preparations, it is necessary to apply SPF 50 sunscreen to avoid pigmentation disorders.
Can this combination be used for all acne scar treatments?
No. It is used in isolation, in combination with non-ablative fractional laser or radiofrequency, or weeks after more aggressive treatments such as dermabrasion, CO2 laser or radiofrequency with needles.
What type of acne scars benefit the most from the combination of retinoic acid and glycolic acid?
Although they all benefit from using it, the most superficial ones are the ones that obtain the most improvement: macules – spots – and wavy atrophic scars (rolling). However, it is advisable to use it whenever there are acne scars.
Which is better, to have a chemical peel in the office or to apply a combination continuously at home?
These are not two incompatible procedures. However, it is preferable to perform a topical treatment consistently and for a prolonged period of time rather than a specific chemical peel (salicylic acid or glycolic acid) sporadically. More benefit will be obtained in the long run, the duration of the effect will be longer and the costs of the aesthetic treatment will be reduced. If we add periodic medical peels to that, the effect will be superior and the treatment will be controlled by a dermatologist, which is optimal.
REFERENCES
· Chandrashekar BS, Ashwini KR, Vasanth V, Navale S. Retinoic acid and glycolic acid combination in the treatment of acne scars. Indian Dermatol Online J. 2015 Mar-Apr; 6(2):84-8.