A Prospective Study Comparing Clinical Efficacy of 30% Mandelic Acid Peel Versus 30% Lactic Acid Peel in Periorbital Melanosis

Abstract

Background:

Periorbital melanosis (POM), or dark circles, is characterized by hyperpigmentation around the eyes, mainly affecting females aged between 16 to 25 years. It results from genetic and environmental factors. Chemical peels with mandelic acid and lactic acid are commonly used for treatment, but their comparative effectiveness and safety are underexplored. This study compares the effectiveness and safety of 30% mandelic acid peel versus 30% lactic acid peel for treating POM.

Patients and Methods:

A prospective, comparative study was conducted at a tertiary healthcare institute over 18 months (September 2022 to February 2024) with 70 patients. They were randomly assigned to receive either mandelic acid (35 patients) or lactic acid peels (35 patients) across three sessions (weeks 0, 2, and 4), followed by an end of study visit at week 6. Efficacy was measured using the POM grading, visual analog scale (VAS), and patient satisfaction score, while safety was assessed via adverse events.

Results:

Both treatment groups showed significant improvement in POM severity, with a shift from higher to lower grades of pigmentation. However, the lactic acid group exhibited a significantly greater reduction in pigmentation (50% of patients with more than 30% improvement in VAS, P = 0.001). Patient satisfaction was higher in the lactic acid group (100% satisfied vs. 83.9% in the mandelic acid group, P = 0.011). Side effects included mild erythema and swelling, with exfoliation more common in the lactic acid group and irritation more frequent in the mandelic acid group.

Limitations:

This study is limited by its small sample size and short duration, which may impact the generalizability and long-term evaluation of the treatments.

Conclusion:

Both 30% mandelic and lactic acid peels effectively treated POM, with lactic acid showing better outcomes and patient satisfaction. Both treatments were safe, but lactic acid may be better for sensitive skin due to milder side effects. Larger studies with longer follow-up are needed.

Introduction

Periorbital melanosis (POM) is characterized by the presence of bilateral hyperchromic macules, that primarily involve the lower eyelids, although it may affect the upper eyelids, eyebrows, and surrounding areas.[1] Commonly known as periocular hyperpigmentation or dark circles, POM predominantly affects women aged from 16 to 25 years, with onset typically occurring after puberty.[2]

The development of POM is attributed to a combination of endogenous factors, such as genetics, age, vascularity, vitamin K deficiency, chronic sinusitis, anemia, atopy, and thin skin, as well as exogenous influences including sun exposure, fatigue, post-inflammatory hyperpigmentation, sleep deprivation, stress, environmental pollution, airborne/contact allergies, and hormonal therapies.[1,3] It often follows an autosomal dominant inheritance pattern.[4]

Clinically, POM can be classified based on its profile and vasculature into several types: constitutional, post- inflammatory, shadow effect, vascular, and others, including factors like skin laxity, hormonal disturbances, malnutrition, chronic illness, sleep deprivation, acanthosis nigricans, and personal habits, or a combination of these influences.[5]

Despite being common, treatment options for POM remain limited. Available approaches include topical treatments such as retinoic acid, chemical peels, vitamin C, LASER therapy, injectable fillers, and surgical procedures like blepharoplasty.[6] Chemical peels are especially favored among these due to their proven effectiveness and shorter recovery periods.

Chemical peeling works by inducing controlled damage to the skin, stimulating epidermal regeneration with or without affecting the dermis.[7] The application of a caustic agent typically leads to a “white frost,” indicating the depth of the peel. Ideally, chemical peels aim for minimal frosting (Level I) to ensure effective exfoliation without penetrating too deeply into the dermis.[8]

Recently, lactic acid (LA) and mandelic acid (MA) peels have gained popularity as agents for superficial peeling, offering comparable effectiveness to glycolic acid (GA) but with less discomfort and minimal downtime or risk.[8] Due to its larger molecular size, MA penetrates the epidermis more slowly, making it gentler and suitable for all skin types. It also boasts antibacterial and anti-inflammatory properties, which help reduce dryness and irritation. Effective concentrations range from 20% to 50%, promoting skin rejuvenation and addressing pigmentation and acne issues.[1]

Due to their lower pH, LA peels provide significant exfoliation at lower concentrations compared with GA. In addition, they inhibit the tyrosinase enzyme, contributing to reduced pigmentation. Recovery from LA peels usually involve a few days of exfoliation, with full re-epithelialization typically occurring within 7 to 10 days.[9,10]

While both acids have demonstrated benefits in the treatment of hyperpigmentation, their comparative efficacy and safety in the management of POM remain underexplored.

This study aimed to evaluate and compare the clinical efficacy and safety of 30% MA peel versus 30% LA peel in patients with POM. By addressing this gap in the literature, we seek to provide evidence-based insights into which treatment modality offers superior outcomes in terms of both therapeutic efficacy and patient safety, thus guiding clinical practice in the management of this challenging cosmetic condition.

Patients and Methods

This prospective, comparative study was conducted to assess the clinical efficacy and safety of 30% MA peel versus 30% LA peel in patients with POM. The study was carried out at Amaltas Institute of Medical Sciences, Dewas, over a period of 18 months from September 2022 to February 2024. Ethical approval for the study was obtained from the Institutional Ethics Committee of Amaltas Institute of Medical Sciences, Dewas, (M.P.) prior to its initiation of the study (date of approval- 26.08.2022). The study included patients aged 18 years and older who were diagnosed with POM and had not received any prior treatment for the condition. All the participants were informed about the study objective, and informed consent was obtained in their preferred language (English/Hindi). Patients with allergies to the constituents of chemical peels, those with active infections or inflammatory skin conditions (such as seborrheic dermatitis or atopic dermatitis), pregnant or nursing women, and those on photosensitizing drugs were excluded. Patients who did not provide informed consent or were unwilling to participate were also excluded from the study.

A total of 70 patients who met the inclusion criteria were recruited and randomly assigned to one of two treatment groups using computer-generated numbers: Group 30% MA peel or Group 30% LA peel. A detailed clinical history and examination were performed for each patient prior to the treatment. Each participant received three chemical peel sessions at baseline (week 0), week 2, and week 4. The chemical peel was applied for a contact time of approximately 10 minutes. After the final peel session at week 4, patients were assessed at week 6 (end of study).

The primary outcome of the study was the clinical efficacy of the two treatments, which was evaluated using the POM grading, visual analog scale (VAS), and patient satisfaction score (PSS). The POM score was used to grade the severity of pigmentation on a scale from grade 0 (no pigmentation) to grade 4 (severe pigmentation extending beyond the infra-orbital fold).[2] Improvement in pigmentation was assessed using VAS scale by the investigator. A 5-point Visual Analog Scale (VAS) was employed, where a score of 1 indicated worsening, 2 indicated no change, 3 corresponded to <30% improvement, 4 to 30–60% improvement, and 5 to >60% improvement. For analytical purposes, a threshold of <30% improvement was considered as no or minimal change, whereas ≥30% was taken to represent a clinically meaningful improvement. It was initially assessed at baseline (week 0) and finally at week-6. Patient satisfaction was evaluated using the PSS, where grade 0 indicated not satisfied, grade 1 indicated moderately satisfied, grade 2 indicated greatly satisfied but not fully, and grade 3 indicated fully satisfied. For statistical analysis, responses were grouped as: Satisfied (grades 1 to 3) and Dissatisfied (grade 0). At each visit, safety was assessed by documenting any adverse effects such as erythema, exfoliation, irritation, tenderness, or swelling.

The sample size was calculated based on previous study showing a 73.34% improvement with traditional treatments[11] with an expected 15% greater improvement from the chemical peel treatments. Using a sample size calculation formula (n = (Zα/2)² * (p * q)/L²), the estimated required sample size was 63. Accounting for a 10% dropout rate, 70 patients were enrolled.

This study was self-funded, with no charges imposed on the patients for participation and chemical peels. However, the patients covered the routine outpatient procedural charges (as per the institution’s established schedule of charges) and post-procedural prescriptions including sunscreens and moisturizers. Patient confidentiality was strictly maintained, and all personal information was protected. Data relevant to the research objectives were collected and analyzed in accordance with ethical guidelines.

Data analysis was conducted using IBM SPSS version 21.0 for statistical analysis and Microsoft Excel 2016 for graphical representation. Categorical data were analyzed using the Chi-square test or the Z test for two-sample proportions. Quantitative data were assessed with the unpaired t-test for normally distributed data or the Mann-Whitney U test for non-normally distributed data. A P value of less than 0.05 was considered statistically significant.

Results

Group distribution

The study comprised 70 patients, equally divided into two groups: 35 (50%) in Group-LA and 35 (50%) in Group-MA. Among the 70 patients, 61 completed the study.

Age distribution

The mean age of patients was 27.29 ± 6.04 years in Group-LA and 26.83 ± 7.47 years in Group-MA. There was no significant difference between the groups with respect to age (P = 0.779).

Gender distribution

Group-LA consisted of 26 females (74.3%) and nine males (25.7%), while Group-MA had 24 females (68.6%) and 11 males (31.4%). The proportion of females was significantly higher in both groups (P = 0.001). There was no significant difference between the two groups regarding gender (P = 0.597).

Periorbital melanosis (POM) grading

Group-LA: At baseline, the majority of patients had Grade 3 (45.7%) or Grade 2 (22.9%) POM. There was a significant improvement by the end of study, with 10% of patients achieving Grade 0 and 40% in Grade 1. The shift from higher grades (3 and 4) to lower grades (0, 1, and 2) was significant (P = 0.001) [Table 1, Figure 1].

Table 1.

Comparison of periorbital melanosis (POM) grading in Group-LA and Group-MA from baseline to end of study

Group	POM Grading	Baseline (Week-0) (n=35)	Second Session (Week-2)	Third Session (Week-4)	End of study (Week-6)
Group-LA	Grade 0	0	0	0	3
		0.0%	0.0%	0.0%	10.0%
	Grade 1	5	5	7	12
		14.3%	14.3%	21.9%	40.0%
	Grade 2	8	13	15	12
		22.9%	37.1%	46.9%	40.0%
	Grade 3	16	13	10	3
		45.7%	37.1%	31.3%	10.0%
	Grade 4	6	4	0	0
		17.1%	11.4%	0.0%	0.0%
	Total	35	35	33	30
		100.0%	100.0%	100.0%	100.0%
Group-MA	Grade 0	0	0	0	2
		0.0%	0.0%	0.0%	6.5%
	Grade 1	3	3	6	11
		8.6%	8.6%	17.6%	35.5%
	Grade 2	14	17	17	10
		40.0%	48.6%	50.0%	32.3%
	Grade 3	11	9	8	8
		31.4%	25.7%	23.5%	25.8%
	Grade 4	7	6	3	0
		20.0%	17.1%	8.6%	0.0%
	Total	35	35	34	31
		100.0%	100.0%	100.0%	100.0%

POM, periorbital melanosis; LA, lactic acid; MA, mandelic acid

Figure 1.

Patient received lactic acid peel- before and after treatment

Group-MA: Baseline POM grading showed a similar distribution, with 40% in Grade 2 and 31.4% in Grade 3. By the end of study, 6.5% of patients achieved Grade 0, and 35.5% were in Grade 1. A similar shift in POM grades was observed, which was also statistically significant (P = 0.001) [Table 1, Figure 2].

Figure 2.

Patient received mandelic acid peel- before and after treatment

At baseline, there was no significant difference in the distribution of POM grades between the two groups (P > 0.05 for all grades). At the end of study, no significant differences in POM grades were found between the groups (P > 0.05).

Visual analog scale (VAS)

In Group-LA, 50% of patients showed a change in VAS of more than 30%, while in Group-MA, this was 19.4%. There was a significant improvement in VAS score in Group-LA compared with Group-MA (P = 0.012) [Table 2].

Table 2.

Comparison of patients according to VAS improvement and PSS at last visit from baseline

	Group		Z test for two-sample proportion applied, P
	LA	MA
VAS Change
>30%	15 (50%)	6 (19.4%)	0.012*
≤30%	15 (50%)	25 (80.6%)
Total	30	31
PSS
Satisfied	30 (100%)	26 (83.9%)	0.011*
Dissatisfied	0 (0%)	5 (16.1%)
Total	30	31

*P<0.05 was considered statistically significant. VAS, visual analog scale; PSS, patient satisfaction score; LA, lactic acid; MA, mandelic acid

Patient satisfaction score (PSS)

In Group-LA, all 30 (100%) patients were satisfied, while in Group-MA, 26 (83.9%) patients were satisfied. The satisfaction rate was significantly higher in Group-LA compared with Group-MA (P = 0.011) [Table 2].

Adverse events

When comparing adverse events between the two groups, exfoliation was reported less frequently in Group-MA (5.7%) than in Group-LA (14.3%). Conversely, irritation was more common in Group-MA (28.6%) compared with Group-LA (14.3%). Erythema and swelling occurred at similar rates in both groups [Figure 3].

Figure 3.

Bar diagram showing comparison of adverse events between the two groups

Discussion

In this prospective comparative study, 70 participants were evenly distributed in a 1:1 ratio between two treatment arms—Groups LA and MA—to assess their efficacy and safety in treating POM. Both groups were comparable in terms of the patients’ age. However, we observed a higher proportion of females in both groups, which may be attributed to the greater likelihood of women seeking clinical treatment for cosmetic concerns. These findings are consistent with those of Gendler et al.[12]

Both treatment groups in our study showed significant improvements in POM grading after three sessions. Specifically, 10% of patients in the Group LA reached Grade 0, while 6.5% in the Group MA achieved the same, suggesting that both treatments elicited a positive response. This aligns with the results from Ahmed et al.,[13] who reported significant improvements in POM with both LA and GA peels, further reinforcing the effectiveness of chemical peels in treating POM. Similarly, Dayal et al.[11] observed substantial improvement in POM with both GA and LA peels, supporting the potential of alpha-hydroxy acids in this context.

Our study found no significant difference in POM grades between the LA and MA groups. This contrasts with the findings of Sawle et al.,[14] who demonstrated that a 30% MA peel was more effective than a 15% LA peel and a 10% trichloroacetic acid peel. This discrepancy suggests that the concentration of peel agents plays a key role in determining their relative effectiveness, emphasizing the importance of formulation and concentration in achieving optimal results. Furthermore, our VAS results showed that 50% of patients in the LA group experienced a change of more than 30%, compared with only 19.4% in the MA group, highlighting a statistically significant difference in perceived improvement. This differs from the findings of Ahmed et al.,[13] where significant improvements were reported with GA and LA peels, but no direct comparison to MA was made.

In terms of patient satisfaction, 100% of patients in the LA group reported being satisfied with their treatment, compared with 83.9% in the MA group. This contrasts with Dayal et al.,[11] where GA peels resulted in the highest levels of satisfaction and improvement, suggesting that patient preferences may vary depending on the type of chemical peel used. In addition, we noted differences in adverse events: exfoliation was more common in the LA group (14.3%) compared with the MA group (5.7%), while irritation occurred more frequently in the MA group (28.6%). These findings align with Dayal et al.,[11] who also reported varying side effect profiles among different chemical peels, underscoring the need for individualized treatment plans based on patient tolerance.

Limitations

The study was limited by a small sample size, which may limit the generalizability of the study results. The short duration of the study may not be sufficient to assess long-term efficacy and the potential for recurrence of POM after treatment cessation.

Conclusion

The study concluded that 30% LA peels outperformed 30% MA peels in improving POM. Patient satisfaction was higher with LA (100% vs. 83.9%). Both had similar side effects, but LA caused more exfoliation, while MA led to more irritation. Despite limitations like small sample size, LA may be more effective, though treatment should be tailored to individual needs.

Conflicts of interest

There are no conflicts of interest.

Use of artificial intelligence (AI)

While the content was originally conceived and drafted by the author, AI tool (chatgpt) was utilized to assist with grammar, style, and clarity.

Funding Statement

Nil.