Healthcare e-Compendium
A joint initiative of DPSRU & DRSC
Healthcare e-Compendium
A joint initiative of DPSRU & DRSC
Author: Dr. Aakanksha Juyal
M.B.B.S, D.DVL, Dr. Aakansha's Skin and Cosmetology Clinic, Lucknow
download ArticleAbstract
The sun and its UV rays are harmful for skin and human body; photoprotection is a desirable preventive option. There are different types of UV rays which have several adverse effects on skin. Topically, the harmful UV rays can be prevented by using sunscreen. While choosing a sunscreen it is advisable to know about the properties and type of the sunscreen with the active chemical ingredients present in it.
Keywords: Gel-based sunscreen, Sunbeat, UV radiation, Photoprotection
Introduction
In the recent times, skin diseases and their awareness have become a major concern. A significant increase of skin cancer in the Western countries and in fair skinned population have drawn the attention towards the exposure of sunlight and the harmful ultraviolet rays of the sun. The ultraviolet rays of the sun are mainly a form of electromagnetic waves that comes from the sun, though these UV rays comprises a small amount of sun rays. Different types of UV rays reach the different layers of the atmosphere in different amounts. About 95% of the UV rays from the sun that reach the ground are UVA rays, with the remaining 5% being UVB rays [1]. UVC rays does not have harmful adverse effects as it does not reach the earth’s surface because of the ozone layer in the atmosphere.
The main concern with the harmful UV rays from the sun arises with long term exposure. Prolonged exposure of UV rays results in both acute and chronic health effects on skin and eyes. Sunburn and sun tanning are very common acute effects of UV radiation exposure. While in the long term, UV radiation-induced degenerative changes in cells, fibrous tissue and blood vessels lead to premature skin aging; it can also cause inflammatory reactions of the eye, such as photokeratitis [2].
The best effective ways to prevent UV rays is to use a sunscreen as a photoprotection method. Photoprotection is the reduction of UV rays induced skin damage and skin cancers [3]. This comprises sunscreens, windshields, hats, sunglasses and clothing.
Types of Ultraviolet Rays
The radiation is classified into three different types - ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC). These are specifically measured according to their wavelength, measured in nanometers (table 1) [4].
Table 1: Wavelength of different types of ultraviolet radiations
|
WAVE TYPE |
UVA |
UVB |
UVC |
|
Wavelength |
315-400 nm |
280- 314 nm |
100-279 nm |
|
Absorption Level |
Not absorbed by the ozone layer |
Mostly absorbed by the ozone layer, but some reaches the Earth’s surface |
Completely absorbed by the ozone layer and atmosphere |
The earth’s ozone layer plays an important role to absorb most of the UVB rays and complete UVC rays. UVA rays reaches the earth’s surface and are known for the adverse effects on health. Although UVA rays are weaker than UVB, it penetrates deeper into the dermal layer and causes premature ageing, skin damage and many other diseases.
Ultraviolet Rays and Health Issues
Skin Ageing and Sunburn:
The most known acute effect of overexposure of sun and its harmful rays is known as erythema, which is skin redness commonly termed as sunburn. While dark skinned people get it as suntan due to the stimulation of melanin production by UV rays. When these acute effects remain untreated or unprotected, the outermost layer of the skin thickens which attenuates UV penetration into deeper dermal layer [5]. Gradually, skin loses the elasticity due to collagen degradation and accelerates skin ageing, dry and rough skin.
Skin Cancer:
Exposure to UV radiation can also cause various forms of chronic effect like degenerative changes in cells, blood vessels, keratinocytes and tissues of the body [5]. These are known as freckles, solar lentigines, mainly diffuse brown pigmentation with patches on skin. These conditions are often termed as photoaging (solar elastosis). Ultraviolet radiation can directly cause damage to the genetic level (that is, DNA) which further cause various skin cancers.
Skin cancer is predominant and serious with fair-skinned people due to less production of melanin. There is still a misconception with almost every person, that is, individuals with fair skin need to be concerned about long exposure to the sun. Melanin production has a very important role in protection against UV rays from sun. The darker skin has more melanocytes than fair skin, which produces the protective pigment called melanin. So, the occurrence of skin cancer is less in dark skinned people.
Sun exposure causes cutaneous melanoma and non-melanocytic skin cancer [6]. Squamous cell carcinoma which is a form of non-melanoma skin cancer is mostly seen to affect head and neck, the most exposed area to the sun. This gives a distinct implication that long-term UV exposure is an important major factor. The non-melanoma skin cancer is rarely fatal but the surgeries involved as treatment methods are painful.
The malignant melanoma is not seen frequently and is less in incidence compared to non-melanoma skin cancer. This is more common among people with a pale complexion, blue eyes, and red or fair hair. Nevertheless, melanoma or skin cancer also occurs in this population which gets detected at a late stage with more fatal consequences. Moles are also commonly at a risk of melanoma in fair skinned population.
Besides, the other adverse health effects of UV rays are independent of skin type and its complexion like damage to immune system and eyes [7].
Eyes:
Sunrays have acute effects like photokeratitis and photoconjunctivitis (painful eye conditions). Although the damages from these conditions are reversible and do not continue to pose any long-term threats to vision. Another common leading adverse effect is Cataract, causing blindness. It is caused by accumulation of pigments which blocks the eye’s lens, making it cloudy. Exposure to UVB rays in particular appears to be a major risk for cataract development.
Immune System:
Exposure to sunlight is known to be beneficial to the human body, as it synthesizes and produces Vitamin D, a vital vitamin for the immune system and the overall development of the body. WHO (World Health Organization) recommends 5-15 minutes of sun exposure for vitamin D synthesis, which is fulfilled by short duration of exposure to sunlight in the morning hours, when the rays will not be intense. The daily over exposure will cause harm, on the other hand will increase the chances of cancer due to suppression of immune responses. Exposure of ultraviolet radiations of sun reduces the body’s defense mechanism, which generally limits the development of tumours [7].
Daily usage of sunscreen, limiting the daily total time of exposure to sunlight and taking proper protection by covering the skin with clothes can save or reduce the adverse effects to human health.
Sunscreen Know How
Increase in awareness of skin cancers, melanomas, sunburns have increased the demand of sunscreen over the past few decades. At recent times, different types and formulations of sunscreens are available in the market. Detailed features need to be known before picking up a sunscreen for photoprotection.
Sunscreen and its Types:
Sunscreens are mainly barrier on the skin that works by reflecting and scattering light, or sometimes absorbing it. Based on the two mechanism of action of topical sunscreen. it is divided into 2 types – Chemical sunscreen and Physical sunscreen.
Chemical sunscreen: These are also known as organic sunscreens. The chemical structure has an aromatic compound with carbonyl group which allows UV rays of high energy to get absorbed in excited state. Then the longer wavelengths of lower energy are released on returning to its ground state. They consist of both UVA and UVB blockers (table 2) [8].
Table 2: Examples of UVB and UVA blockers
|
UVB blockers |
UVA blockers |
|
|
Physical sunscreen: These are inorganic and also called mineral sunscreen, which works by reflecting and scattering of UV light. The properties of reflection measure the effectiveness of sunscreens. The properties are mainly based on the reflective index, size of particles and dispersion of base. Higher reflective index means better UV protection and UV filter. The sunscreens have zinc oxide and titanium dioxide commonly. They protect against UVA but does not react to it and are photostable [9].
Physical sunscreens have advantages of reflecting the UVA rays of different wavelengths, but are not effective against UVB rays. These sunscreens are skin-friendly as they do not get absorbed in the skin and acts as a protective layer on top of the skin, though they leave a white cast after applying. While chemical sunscreens consist of UVA and UVB blockers, but they get absorbed in the skin and some chemicals have carcinogenic effects and skin irritating properties.
UV Hold Ultra Gel-based Sunscreen
A unique, quick drying, water soluble, non-greasy and clear sunscreen gel with maximum UV protection to protect from harmful UV rays with a SPF30 (sun protection factor). It contains Methoxycinnamidopropyl Hydroxysultaine, Porphyra umbilicalis extracts, Vitiver extracts, Cucumber extracts, Carrot extracts, Aloevera extracts and Chamomile extracts with sunbeat formulation. It is best for oily and acne prone skin.
Porphyra umbilicalis extract is from the red algae which produces powerful UVA absorbing substances at 335nm wavelength absorption, a natural UVA protection factor for daily use, that protects from premature aging signs like wrinkles, fine lines and also protects DNA from damage.
Vitiver extract is known to be a powerhouse of antioxidant and has high water retention capacity. It has soothing properties which nourishes skin, reduces inflammation and treats acne.
Cucumber extract is known for its cooling effect, thus soothes skin and absorbs UVB radiation as a potent sun protection.
Aloe vera extract helps to prevent peeling of skin and has anti-inflammatory properties while moisturising the skin.
Chamomile extract helps protect against long and short-term skin inflammation, soothes skin and alleviates redness of skin. It contains high level of antioxidant known as apigenin.
Sunbeat is a molecule, Methoxycinnamidopropyl Hydroxysultaine, a colourless to pale yellow in colour and has zwitter ionic surfactant. Due to the property of zwitter ions, it acts as an excellent emulsifying agent because of which it improves the properties of the inorganic fluids and extracts [11]. The water solubility of this sunscreen has made it beneficial for oily and acne prone skin. It dries out fast without being sticky, making the skin smoother for extracts added to it, as previously discussed. UV hold ultra-gel forms a uniform layer and rests on the top of the skin (figure 1) and scatters harmful rays without absorbing or entrapping the heat in skin layer, which causes comedones by clogging pores. The gel is full of benefits with antioxidants and natural extracts, which does not leave any white cast compared to other mineral sunscreen.
Figure 1: Mechanism of Sunbeat to prevent UV rays from damaging skin
Guide to choose a sunscreen:
Conclusion
The use of sunscreen is an important component to sun protection. UV rays of sun causes most of the damage to skin leading to various diseases. An individual need to be aware of the skin type and use sunscreen accordingly. There are variety of formulations of sunscreen available. The awareness of UV light and also blue light emitted from laptops and other electronic devices in indoors should be discussed. A topical sunscreen alone will not be as effective as a combination of it with clothes and wide brimmed hat. The daily use of sunscreen will help to reduce the burden of skin diseases and cancers.
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