Updates on Dermatology: Hyperpigmentation

Over the last ten years, several studies have shown that besides the well-known damaging effects of ultraviolet radiation (UV), both visible (VL, 400-700 nm) and infrared light (> 700 nm) also cause damage which contributes to photoageing.(1) UV is the main cause of skin pigmentation, but VL is also an important contributor, especially in melano-competent subjects.(2) Furthermore, there is increasing evidence on the role of VL in pigmentary disorders in dark-skinned and immediate erythema in light-skinned individuals.(3,4) Thus, photoprotection from VL light may help to improve several hyperpigmentation disorders.(5)

Broad-spectrum sunscreens protect against UV but do not adequately protect against VL. A sunscreen that protects efficiently against VL, must be visible on the skin.(6) Mineral filters, especially, zinc oxide and titanium dioxide, are currently used as nanoparticles in sunscreens to minimize the chalky and white appearance on the skin. However, they do not protect against VL. Tinted sunscreens containing opaque pigments with large particle sizes, such as iron oxides, are the only currently available, efficient topical photoprotection products against visible light-induced hyperpigmentation.(7) Tinted sunscreens use different formulations and concentrations of iron oxides and of pigmentary titanium dioxide. Iron oxides and mineral filters have different absorbance profiles, and many shades of tinted sunscreens are available by combining different amounts of iron oxides and pigmentary titanium dioxide to cater to all skin phototypes.(6) With tinted sunscreens having different formulations and concentrations of iron oxides and pigmentary titanium dioxide, it is critical that the tinted sunscreen color matches the skin color of the patient. A broad-spectrum sunscreen is necessary to protect against VL, UVA, long-wave UVA, and UVB. Thus, recommending the right type of sunscreen can be challenging.

Recommendations to assess VL protection of sunscreens have been issued.(8) These recommendations confirm that:

1. Cell-based in vitro studies are only suitable for screening compounds;
2. Methods based on reactive oxygen species (ROS) should not be used to assess the protective effects against VL -induced hyperpigmentation;
3. The in vitro pigmentation protection factor (PFF) based on transmission reduction of VL appears to be the most adequate in vitro method for topical formulations;
4. In vivo models should always be considered the gold standard.(8)

A study assessing the transmission spectra of 10 broad sunscreens and involving subjects with a Fitzpatrick skin phototype III to V reported that the most effective protection was against high-energy visible light(9). A strong correlation between in vivo visible light protection factor and in vitro transmittance measurements was observed, with the highest correlation factor at 420 nm and in the spectrum covering from 400 to 469 nm.(9) Transmittance measurements were found to be a good predictive tool to evaluate the VL photoprotection efficacy of a given sunscreen allowing to select formulations for final in vivo testing.(9)

In that same study, the reference visible light photoprotection factor VL-PF was also expressed as a percentage using the formula (1-(1/VL-PF))×100, called the pVL-PF, in order to facilitate comprehension by dermatologists and patients Therefore, the pVL-PF is a new interpretation of the original VL-PF to compare more intuitively from 0% to 100% the performance of different formulations on VL-induced pigmentation. For this reason, in vitro methods using transmittance measurements from 400 to 469 nm are predictive tools to evaluate VL photoprotection efficacy of sunscreens.

Facial hyperpigmentation disorders include melasma, post-inflammatory hyperpigmentation (PIHP) and solar lentigines. They are common, difficult to treat and may have an important impact on the subjects' quality of life.(1) Key challenges in the management of pigmentary disorders, are their resistance to treatment, tendency to recur after treatment, and the risk of exacerbating hyperpigmentation when using many treatment modalities.(2)

For many years, the gold standard for the dermatological treatment of hyperpigmentation has been the Kligman’s trio, consisting of hydrocortisone, retinoic acid, and hydroquinone, each with a different effect (anti-inflammatory, cell renewal accelerant, and melanin decrease in the epidermis, respectively) . (3) This triple combination has shown its efficacy overtime. However, its use is limited to 2 months twice a year, leaving subjects without treatment 2/3 of the year. Moreover, after treatment, relapses and hypersensitivity, such as irritation or hyperpigmentation, have been observed.(4)

NAOS is the pioneer in ecobiology, a unique scientific approach that uses the in-depth knowledge in skin biology to protect its ecosystem. By observing, understanding and mimicking the natural mechanisms of the skin, ecobiology favours biomimetic ingredients that help the skin strengthening and replicating itself and stimulates its natural rebalancing and regeneration mechanisms, thus allowing to balance and regenerate itself.

Within this context, BIODERMA developed a specific skin care, Pigmentbio ®, a complete line of products that allows to manage hyperpigmentation issues all over the year.

The product range Pigmentbio ® include two types of ingredients: one to reduce dark spots, the LumirevealTM technology, and a combination of vitamins acting as skin barrier support to optimize skin recovery.

The LumirevealTM technology mimics the Kligman’s trio mode of action, with glabridin as an anti-inflammatory, while EpidermactivTM accelerates cell renewal, and the combination of andrographolide plus azelaic acid decreases the melanin level in the epidermis. Skin barrier support is provided by a combination of vitamin C and vitamin E, an antioxidant that prevents skin ageing and melanin darkening, and niacinamide which reinforces the natural skin barrier.(5)

In addition to the LumirevealTM technology and to 2% fresh vitamin C which was added to reduce dark spots, Pigmentbio® C-Concentrate contains 2% salicylic acid and 8% glycolic acid, for a “peeling-like” effect, and 2% niacinamide plus 0.5% vitamin E for skin hydration and to prevent visible signs of ageing shown by a clinical study in women with melasma.(6) In this study, the melasma area and severity index (MASI) score had decreased by 10% after 2 months of daily use and kept on decreasing while the subjects were only using Pigmentbio ® Daily-care SPF 50+ plus Pigmentbio ® C-Concentrate. After five months, the MASI score had decreased by 25% compared to baseline. In another study involving 41 subjects with melasma, the MASI score was divided by 2 after 3 months of sun care protection and application of Pigmentbio ® C-Concentrate.(7) When used alone, Pigmentbio ® C-Concentrate increased skin hydration in 90% of subjects, acted as an 8-hour moisturizer, and was very well tolerated in all subjects.(7-9)

Preventing hyperpigmentation is an important issue. Blue light is directly involved in melasma. BIODERMA has developed Photoderm ® M SPF50+, a blue light protection sunscreen with antirecurrence efficacy, high coverage, and a matte finish for dark spots and melasma. The Sun Active Defense technology in Photoderm ® M SPF50+ is based on the combined effects of SPF50+, UVA39, and a clean filtering association. By combining pigments (10.7%) and iron oxide, 61 to 66% of blue light reaching the skin is blocked (Figure 1). (10)

Clinical investigations showed a significant decrease in the MASI index (-31.8%, p<0.001) in subjects with melasma using Photoderm ® M SPF50+ for 4.5 months. (11) In addition, the cosmetic qualities of Photoderm ® M SPF50+ generated better subject compliance. In other studies, 97% of the subjects had an improved quality of life, due to the high coverage of pigmentary spot, 89% of subjects stated that Photoderm ® M SPF50+ leaves a pleasant powdery finish, and 93% considered that it held well throughout the day.(12-14)

Through their ecobiological approach, Photoderm ® M SPF50+ and Pigmentbio ® C-Concentrate, present an combining high efficacy, high tolerance, and high compliance for both the well-being of the skin and that of the subject. By combining high technology and sensory appeal, daily application is promoted, thus increasing the chances of success in preventing hyperpigmentation and its recurrence.