We don’t realize but childhood is a particularly crucial period for sun protection as a child’s skin is thinner as compared to adults, has lower melanin content and a higher surface area to body mass ratio. Studies demonstrate that sun exposure during early life, especially childhood and adolescence, is a strong determinant of future risk of skin cancer/melanoma.
Children are unable to understand the consequences of excess sun exposure or adopt sun protective practices independently and are dependent upon their parents to implement such protection. Especially the adolescents’ sun protection behaviours are difficult to target due to negative attitudes towards the use of sun protection and significant peer influences.
Parents also describe various advantages associated with sun exposure, including playing outdoors, building up tolerance to the sun, and mental well-being with the most commonly mentioned reason being the need for vitamin D (especially true in Indian settings, where almost everybody is found to be Vitamin D deficient). This makes it challenging in some cases to achieve a balance and know when protection is warranted.
Although sunscreen is the most commonly used modality for sun protection, there is a massive confusion about how sunscreens work and mixed perceptions as to the amount of protection they offer, as well as concern over potential side effects associated with their use, such as systemic toxicity and vitamin D deficiency. The unclear labeling of sunscreen products along with no regulatory guidelines in India has added more to this confusion.
In this article I will try to, discuss effect of UV radiations, how sunscreens work to protect us and interpret current sunscreen terminology along with the current recommendations on proper use of sunscreens and consideration for sun-protection interventions among children and adolescents worldwide including Indian scenario as well.
What is ULTRAVIOLET RADIATION ??
Ultraviolet radiation of sunlight is comprised of UVA (315–400 nm), UVB (280–315 nm) and UVC (100–280 nm) radiation, based on wavelength. Whereas the ozone layer completely blocks UVC radiation and UVB radiation of wavelengths below 295 nm, 90–95% of the UV radiation that reaches the Earth’s surface is UVA, with UVB accounting for most of the remainder. The amount of exposure to UVA usually remains constant throughout the year (thus the importance of using sunscreens in winters also), whereas UVB exposure occurs more in the summer.
Depending on the wavelength, UV radiation has diverse effects on the skin, and these effects can be immediate (e.g. tanning, sunburn) or long-term i.e. may take years to manifest (e.g. premature aging, suppression of immunity, skin cancers). However, it is important to remember that excessive UV exposure is damaging no matter how short or long the exposure is.
HOW DOES A SUNSCREEN WORK
Sunscreens are classified as either ‘ Inorganic/physical’ or ‘organic/chemical’ filters or a combination of both, based on their active ingredient. (Word of caution: organic does not mean that it is natural/herbal).
Physical/Inorganic sunscreens
In ‘physical’ sunscreens the active ingredient is an inorganic compound that works by physically reflecting or scattering the UV radiation. The most common inorganic agents currently used are zinc oxide (better) and titanium dioxide, both of which offer UVA and UVB protection and, in order to achieve sufficient reflection, require a thick application. Others are talc, kaolin etc. They are considered safer and better particularly for children and for sensitized skin with the only disadvantage being that they give the skin a ghostly whitish appearance (Remember the sports people especially cricketers with white faces). This side effect has also been reduced with the introduction of micronized particles.
Organic/Chemical sunscreens
In ‘chemical’ sunscreens the active ingredient is an organic compound that works by absorbing UV radiation and dissipating the energy as heat or light. Most absorb UVB radiation (E.g include Octinoxate, salicylates, octocrylenes, DBT and BMP-new ones etc.), a few absorb in the UVA2 range (320–340 nm), and there is only one FDA-approved organic sunscreen, avobenzone, that absorbs in the UVA1 range (340–400 nm). There are some which absorb both and are called as broad spectrum e.g. Ecamsule, bimotrizinol, bisoctizole etc. Organic sunscreens can cause irritation and skin allergies and thus are usually not advisable for children.
IS THERE AN IDEAL SUNSCREEN AGENT?
An ideal sunscreen should be safe, cosmetically acceptable with ease of application, chemically inert, non-irritating, nontoxic, photo-stable, resistant to water and sweat and able to provide complete protection to the skin against damage from solar radiation. They should also effectively block both UVB and UVA rays, which is possible with an agent that has an SPF of 30 or greater. But unfortunately there is nothing in this world which is ideal. So we look upon the best possible option.
HOW TO DECIDE WHICH IS BEST:
It is important that the terminology used to classify sunscreens is known and then correctly interpreted to ensure the required protection.
1. Sun protection factor/SPF:
Sun protection factor is a laboratory measure of sunscreen efficacy that is based on erythema/redness. Because UVB radiation is about 1000 times more erythemogenic than UVA radiation, SPF is primarily a measure of UVB protection.
It is defined as the ratio of the least amount of UV radiation required to produce minimal erythema on sunscreen-protected skin to that required to produce the same erythema on unprotected skin. For e.g. when a product with SPF 50 is applied, it will protect the skin until it is exposed to 50 times more UVB radiation than that is required to burn the unprotected skin. The SPF of a product is not related to the duration of UV exposure, despite common misperception. Additionally, the relationship between SPF and UVB protection is not linear, meaning that a sunscreen with double the SPF rating does not necessarily mean one can remain in the sun twice as long before becoming sunburnt.
People select products based on their SPF and mistakenly assume that bigger numbers are better. In reality, higher SPF ratings don’t necessarily offer greater protection from UV-related skin damage, especially UVA damage, and may lead users to spend too much time in the sun. Sunscreens with SPF > 50 are termed as inherently misleading. So various countries have regulation capping the upper limit to 50.
UVA protection is also an important consideration when evaluating a sunscreen’s ability to block UV radiation. This is measured by the Persistent Pigment Darkening (PPD) Protection Factor (it is designated by a star rating system, with four stars the highest allowed in an over-the-counter product), but which usually is missing on product info-graph.
A well balanced sunscreen, with a SPF/UVA PF ratio<3, appears to provide the most effective protection against pigmentation, DNA damage, photoimmunosuppression and photodermatosis.
2. Substantivity and photo stability
Substantivity refers to the ability of a sunscreen to remain effective in the presence of adverse conditions, primarily water and sweat.
Misguidance by the manufacturers: Currently the use of the terms ‘sunblock,’ ‘water proof,’ or ‘sweat proof’,’ instant protection’ has been banned. Instead, the label should mention ‘water-resistant’ (40 min) or ‘ very water-resistant’ (80 min) (i.e. the duration of water resistance) to reflect the actual water-resistance. It does not mean complete protection. Furthermore, sunscreens cannot claim to provide sun protection for more than 2 hrs without reapplication.
In India, there are no industry guidelines for standardizing sunscreen agents and there is no detailed list of approved products. The Indian regulatory agency’s official website lists only two combination products as approved drugs: Octinoxate + Avobenzone + Oxybenzone + Octocrylene + Zinc oxide/Titanium dioxide. Most of the products in India are classified as cosmetics.
RECOMMENDED USE OF SUNSCREENS FOR CHILDREN
Sunscreens should be considered a third line of defense after clothing and shade (DON’T RELY ON SUNSCREEN ALONE).
Recommendations by various dermatologists include:
1. Seek shade and avoid the sun between 10 a.m. and 4 p.m. when UV radiation peaks
2. Wear protective clothing including long-sleeved shirt, pants and a wide-brimmed hat. Wear child safe shatter resistant sunglasses with at least 99% UV protection.
3. Be careful in the setting of water, snow, and sand as these surfaces reflect UV rays
4. Regarding proper use of sunscreens
• Who: Everyone, including people of all skin colors and children > 6 months of age, especially kids involved in vigorous outdoor activities. Sunscreen is needed even on cloudy days (as 80% of ultraviolet radiation is still transmitted to earth’s surface on cloudy days) and in the winter at high altitudes
• What: Broad-spectrum, water-resistant (40 mins) sunscreen with a minimum SPF of 30 usually Zinc based and fragrance free are good for kids (6 months and above).
• Where: All exposed areas of the body not protected by clothing. Pay particular attention to vulnerable sites such as the face (avoid eyes), nose, ears, shoulders and dorsal feet
• How: Apply generously and uniformly. Recommended application is 2 mg/cm2 of exposed area. A practical guide would be ” teaspoon rule” i.e. slightly more than half a teaspoon [3ml] for each arm, leg or the face and neck and for adolescents, amount equal to around 35 ml. Do not rub it vigorously.
• When: Every day and year-round. 15 to 30 mins before heading outdoors (Think beyond pools and beaches). Reapply every 2 hrs especially after swimming, bathing, toweling off or heavy perspiration.
• Precautions: Don’t use post expiry sunscreens, keep it stored in shade (😊), avoid using sunscreen- insect repellent combinations, avoid powder and spray sunscreens.
SUNSCREEN AND INFANTS
Because the skin of infants and toddlers is thinner, less concentrated with melanin, and immunologically immature, UV radiation can penetrate the skin more deeply and there is less of an immune response mounted against UV damage, putting them at higher risk for cumulative UV damage and skin cancer.
For these reasons, there are separate recommendations for UV protection in infants.
• Less than 6 months old: Keep out of direct sunlight whenever possible. When going out, cover them as much as possible. Find shade under a tree, umbrella, or the stroller canopy.
• More than or equal to 6 months old: Protect skin with clothing or shade whenever possible. Use sunscreen to cover exposed skin. Choose a broad-spectrum, water-resistant sunscreen with a minimum SPF of 30.
TARGETING THE YOUNG
Up to 80% of total lifetime sun exposure takes place before the age of 18 years. Regular sunscreen use during childhood and adolescence could reduce lifetime incidence of non melanoma skin cancers by approximately 78%.
WHY SUNSCREENS FAIL?
The failure of sunscreens to prevent sunburn is usually due to the way sunscreens are applied by the parents (under application and failure to reapply), cost factor (a 50 ml bottle of sunscreen comes around Rs. 300-400 or more), mismatch between the labeled SPF and that delivered on application to skin and non-compliance ( either due to use of improper formulation or fear about side effects esp acne). The best sunscreen in the world won’t work if you don’t use it properly. Despite explicit recommendations and evidence supporting daily sunscreen use, most people do not use sunscreen on a daily basis, and instead, use sunscreen solely on a short-term basis during outdoor activities.
FORMULATIONS:
Generally, sunscreens are available in the form of creams, lotion, gels, ointments, pastes, oils, butters, sticks, and sprays, which are considered over-the-counter (OTC) products. Gel-based sunscreens are preferred in oily skin and acne. Sprays are convenient but less effective.
ADVERSE EFFECTS:
15-19% sunscreen users show some or other adverse effects. Immediate stinging, burning without visible erythema are common while acne and small papules formation might also occur.
CONTROVERSIES REGARDING USE OF SUNSCREENS
Many controversies surround the use of sunscreens and these concerns have led to misconceptions and confusion among the public.
- Melanoma: Regular use of sunscreen can decrease the incidence of melanoma among white adults but cannot prevent skin cancer.
- Sunscreen toxicity/Nanoparticles: Rigorous safety assessment is done to explore the possibility of local and systemic toxicity, such as sensitization, irritation, phototoxicity, and carcinogenicity. Despite this, some adverse skin reactions and occasional systemic influences have been seen related to the use of sunscreens especially with the development of nanoparticles (still under research), so avoid the nanoparticles based ones in kids till further results.
- Potential systemic influences: Sunscreen products with organic UV filters may penetrate the skin in small amounts (0.1–5% of dissolved filter), whereas inorganic UV filters (e.g. titanium dioxide) do not penetrate the skin, posing no potential risk of systemic toxicity.
- Vitamin D deficiency: Because Vitamin D3, a precursor for the biologically active vitamin D, is formed in the skin after exposure to UVB radiation, there is ongoing concern that sunscreen use could potentially lead to vitamin D deficiency by absorbing UVB radiation and inhibiting vitamin D production. Although various studies have disproved this, it is advised that children and adults under age 70 should obtain the recommended 600 IU of vitamin D a day from food sources such as oily fish, fortified dairy products and cereals, and supplements.
INDIAN SCENARIO:
Some people might argue that above recommendations are not true for Indian context. This argument might be based on Indian skin type. Indian skins are primarily type 4 and 5; which is darker i.e. has higher melanin content and is thicker and therefore acts as a natural sunscreen and hence Indian skin is less prone (not completely immune) to skin cancers. Vis-à-vis Caucasian skins which are type 1, 2 and 3 i.e. fairer skin with lesser melanin so more prone to sunburns and skin cancers (70 times more as compared to dark skin individuals) and hence the strong emphasis on sunscreen use. Also the sweating begins at much lower threshold in Indian skins thereby necessitating the need of frequent reapplications which can be quite expensive else the effectivity is hampered.
So at present there are no set guidelines for sunscreen use in India but most dermatologists do advice its use in children above 6 months of age as per feasibility.
CONCLUSION
The Australian public health protection message “Slip, Slop, Slap” has gained wide acceptance throughout the world to encourage children and adults alike to ‘slip on a shirt, slop on a sunscreen and slap on a hat’ to have the best photoprotection. Whereas there may be concerns regarding the long-term safety of UV filters, the benefits of sunscreens clearly outweigh their potential risks. So it is advisable to use sunscreens for your young ones (> 6 months of age). All efforts should focus on compliance, rather than technical issues of sunscreens.
Sources:
- New Insights About Infant and Toddler Skin: Implications for Sun Protection: Paller et al; Pediatrics June 2011
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