The therapeutic value of glycolic acid peels in dermatology

Introduction

Chemical peeling with glycolic and trichloroacetic acid has become an increasingly popular method to treat a myriad of benign skin disorders. The basic procedure aims at the production of controlled chemical burns of epidermis and/or dermis resulting in exhalation and subsequent resurfacing of the epidermis and a remodeling of collagen and elastic fibers with deposition of glycosaminoglycans in dermis.[1] Since there is a paucity of literature with this modality of treatment in Indian patients, a study was conducted to evaluate the therapeutic efficacy of glycolic acid peels in various cosmetic skin problems.

Materials and Methods

A total of 41 patients of both sexes who attended the Dermatological out patient clinic of a tertiary care teaching hospital in New Delhi with varied skin problems including acne, melasma, post inflammatory hyperpigmentation and superficial scarring, constituted the subjects for this study- Before starting therapy, skin typing and photoageing status was evaluated for all patients according to Fitzpatrick′s and Glogau′s classification systems[2] respectively. Patients clinical details and the nature and severity of lesions were noted. Clinical photographs using standard positioning were taken at week 0 (baseline) and week 16 (completion of study).

Following an informed consent and a test peel, all the patients were primed with tretinoin cream (0.025%) for a total of 2 weeks. Serial glycolic acid (GA) peels were then undertaken at fortnightly intervals. Superficial chemical peels (upto the level of stratum granulosum) were attempted according to Brody′s and Mark Rubin′s classification, keeping in mind the peculiarities of the Indian skin. We started with 10% GA for a period of 1-2 minutes, serially increasing the duration and concentration of 30% GA for five minutes was used. All the patients were advised total sun protection with a broad -spectrum sun screen having SPF of more than 15. Side effects if any, which appeared over the course of therapy were also recorded.

At 16 weeks, patients were evaluated and the response to therapy was graded on a five point scale as good (>60%improvement); fair (31--60%%); poor (< 30%); no change or worse. The final assessment was recorded on the basis of the opinion of the clinician, perception of the patient and photographic analysis.

Results

Among the 41 patients included in the study there were 8 males and 33 females. The patients were in the age group of 16-46 years. Skin typing revealed Fitzpatrick type IV in 68.2% type III in 20% and type V in 14% similarly, potoageing status according to Glogau′s classification revealed group I (minimal potoageing) in 51 %, group II in 30% and group III/IV in 19%.

Acne patients comprised 39% of the study group. All of them had a greasy skin with high sebaceous activity. Severity of acne (graded on a four point scale) revealed that mild to moderate acne comprised 50% of the patients while severe acne were seen in 43%. There was a single patient with nodulocystic lesions. Apart from comedones, papules and pustules, a significant number of our patients also had scarring and pigmentation. After undergoing peels with GA, the therapeutic response was good to fair in 75% of the patients (both on the basis of patients and observer assessment). Patients with post inflammatory hyperpigmentation and scarring showed excellent improvement. Significant decrease in the number of comedones and papulopustules was observed in patients with mild to moderate acne. However, the single patient with nodulocystic lesions did not respond well to therapy.

Fifteen cases of melasma, both molar (53.3%) and centrofacial (46.6) were included.[3] On Wood,s lamp examination, melosma was considered to be epidermal (80%), dermal (13.3%) and mixed (6.6%).[3] There was no correlation between the clinical pattern, age, skin type and ingestion of oral contraceptives or pregnancy. With GA peels, a good to fair response was seen in more than 90% of the patients. The poor responders included patients with dermal type of melasma. Side effects in the form of post-inflammatory hyperpigmentation (2 patients) and GA induced hypopigmentation (1 patient) noted in this group.

In patients with post inflammatory hyperpigmentation induced by superficial burns (2cases) or drugs (3cases), the results were not encouraging with appreciable response being seen in only 40% of the patients.

Five cases of superficial scarring of varied etiologies (post herpetic, post TCA application and rhytides) were treated with peels and good to fair response was seen in 80%of them. Apart from this, overall 80% of the patients had experienced an improvement in their skin texture in terms of a smoother and brighter looking skin.

Mild discomfort and irritation of the skin was seen in 11 of our patients (26.5%) however, none of them discontinued treatment on this basis. Post-inflammatory hyperpigmentation, herpes labialis and glycolic acid induced hypopigmentation were the other side effects observed [Table - 2].

Discussion

Chemical peeling is based on the scientific principle of skin healing pattern seen with chemical burns. For centuries, this method of skin rejuvenation has been in vogue, though in less refined ways. This is reflected out in the use of sour milk by Cleopatra centuries ago. Since then a myriad of chemicals have been used as peeling agents, out of which the most fruitful ones are the alpha hydroxy acid (ANA′S). These have been shown to improve photodamaged skin and fine wrinkles[4],[5] and modulate stratum corneum barrier function.[6] GA, a member of AHA family is one of the most commonly used and versatile peeling agent. It has been found used in a variety of skin disorders including disorders of keratinization (xerosis, ichthyosis) apart from the commoner skin problems like pigmentary changes (post inflammatory hype rpigmentation, melasma), acne, wrinkles, warts, actinic and seborrhoeic keratoses etc, the commonest indication being skin rejuvenation. GA is available at lower concentration as home care products, but the dermatologists in practise are the only ones to use concentrations in excess of 20%.[7] Applications of GA peels can enhance the effect of local treatments such as topical steroids in lichen simplex chronicus or psoriasis and topical antifungals in various dermatophyte infections involving palms and soles.

Acne of varying severity has been one of the well-evaluated indications for GA peels. Overall, 75-78%of our patients with acne (except the patient with nodulocystic lesions) showed a good to fair response with GA peels as compared to 90% response seen Wang et al.[8] Upto 69% improvement in scarring and hyperpigmentation seen by Wang et al[8] and Erbgaci et al[7] is also corroborated in our study.

Melasma in the present series showed predominantly a malar pattern (54%) in contrast to the finding by Sanchez et al,[3] where centrofacial melasma was the commonest pattern observed (63%). The incidence of epidermal melasma noticed in the above series was almost similar (72% as compared to 80% in our study). Good to fair results seen in our patients are in agreement with the finding by Lim et al in their study of melasma in Asian women′ and the beneficial effect was clearly outlined in the first two to three serial peels itself.

Burns et al[10] reported a more rapid and better improvement in post inflammatory hyperpigmentation with the use of GA peels. This was reflected in our study also with an overall improvement of skin texture in almost all the patients. GA peels are particularly useful in patients with superficial scarring of varied etiology, as reported in various studies in the past (69% improvement in the study by Wang et al) and also the present study (80% cases showing improvement).

Side effects reported with GA include scarring, infection, post inflammatory hyper and hypopigmentation, atophic texture changes and milia.[11] However, it was found to be quite safe in our study but for minor untoward effects observed in 4/41 patients (9%). This was in close agreement with a 5.6% incidence of side effects seen by Wang et al.[9]

GA is a versatile peeling agent. It alters dermal collagen and matrix via fibroblast modulation[12] and also has an antioxidant action, thus offering photoprotection.[13] In recent years, GA is being used in combination therapy with azelaic acid, tretinoin, ascorbic acid etc. This helps in enhancing the depth of penetration of both agents while decreasing the toxicity and morbidity associated with deeper peels.[14] It is concluded that GA peels in our study were found to be quite effective and safe in the management of some cosmetic skin problems as superficial scarring, melasma, acne and to some extent post inflammatory hyperpigmentation with an overall improvement in texture and rejuvenation of skin.