Chemical peeling - Evaluation of glycolic acid in varying concentrations and time intervals

Introduction

Alpha - hydroxy acids are a class of com-pounds derived from various foods and there-fore called "fruit acid". Glycolic acid comes from sugarcane, malic from apples, tartaric from grapes, citric from citrus fruits and lactic from sour milk.[1],[2],[3] The benefits of AHAs for chemical peeling have long been recognised. Out of all AHAs, glycolic acid is most commonly used for chemical peeling. Present pilot study was un-dertaken to evaluate and standardize the effi-cacy of glycolic acid in three different concen-trations i.e. 35%, 52.5% and 70% with time intervals corresponding to four minutes, three minutes, and two minutes respectively in com-monly encountered dermatological problems.-

Materials and Methods

Thirty-seven patients were selected randomly on clinical basis from Skin and S.T.D. O.P. They in-cluded patients with melasma (31 cases), superfical post acne scarring (4 cases), xeroderma pigmentosum (1 case ), and epidermal naevus (1 case). Minimum age in the study was 17 years and maximum age was 44 years. There were 31 females and 6 males. Patients were advised to use retinoic acid cream (0.025%) at bed time for 2 weeks prior to peeling. During the peel programme, patient was advised to wash his/her face with soap and water. The face was then cleaned with spirit. Then two coat-ings of acetone were applied to ensure even appli-cation of the chemical. After that glycolic acid in re-quired concentrations as in [table] was applied start-ing from forehead-right cheek - chin-left cheek-na-sal bridge-nose-perioral area-upper and lower eye-lids i.e. from least sensitive to most sensitive area for the specified time period. The patient was advised to clean his/her face with ice cold water for termination and neutralisation. All the patients were given sunscreen lotions during day time and emol-lients at bed time. The application was repeated at an interval of 3 weeks for 4 sittings and then monthly for a total duration of 6 months.

Results after 6 months

No significant improvement was noted in cases of melasma where peeling was done with 35% glycolic acid for 4 minutes but, 52.5% glycolic acid applied for 3 minutes in cases of melasma (27 pa-tients) showed significant improvement. 70% glycolic acid applied for 2 minutes in post acne scarring showed significant improvement but 70% glycolic acid applied for 2 minutes in epidermal naevus did not show any significant improvement.

Discussion

The depth of peel usually determines the cos-metic results but in alpha hydroxy acid peel, depth is determined by the agent used, its concentration, volume applied, time of contact, frequency of appli-cation, integrity of stratum corneum and skin thick-ness. Recent interest in AHAs has been rekindled by the work of Van Scott et al.[4],[5] In low concentration, these cause a decrease in corneocyte adhesion but at higher concentration they result in epidermolysis and upper dermal changes producing a vibrant, less wrinkled, more uniformly coloured skin. AHAs have been shown to increase glycosaminoglycans, col-lagen, collagen precursors and factor 13 A, which reverse photo damage and contribute to epidermal and dermal growth factors and mass cell disintegra-tion,[6] as well as regulate homeostasis by keeping the stratum corneum at a suitable thickness to function as a pro-tective barrier.[7]

In our study, maximum benefi-cial effects were noted with 52.5% for 3 minutes in melasma and 70% for 2 min-utes in post acne scarring. Minimum side effects were noted with 52.5% concentration in form of erythema, or burning. As the peels are time and dose related, the longer the exposure to skin and more concen-trated in the solution, the deeper the peel.[8] The in-terval between peels is determined by peel depth, the condition being treated, time and concentration of agent. Glycolic acid chemical peel procedures to-gether with preoperative preparation and post op-erative maintenance have provided a pleasing ad-junct to cosmetic surgical practice in our study.