Science of Skin

Sunscreen and pediatric skin

Photoprotection - skin protection from light and UV - is particularly important for young skin for several reasons:

  •  It has been found that the degree of sun exposure and sunburn in childhood is a central factor in the development of skin cancer, especially melanoma, later in life.  Thus, photoprotection of infants and children is crucial to prevent all types of skin cancer and delay photoaging in adulthood.
  • Children spend a substantial amount of time outside compared to adults.
  •  Infants, toddlers and young children are unable to decide on, and implement, protective measures on their own; thus relying on the conscientiousness of their parents or guardians.
Child_with_sunburn
Figure 1. Sunburnt child (uploaded to flickr.com by 'kirinqueen')

Sunscreens work in two main ways, depending on the active ingredients, either by absorbing the ultraviolet radiation which damages skin, or by reflecting it. There are currently over 20 different ultraviolet filters (chemical and physical ingredients in sunscreen) in commercial use around the world. These come in an assortment of gels, lotions, cream and sprays to suit the particular lifestyle and requirements of individuals.

Characteristics of sunscreen

When choosing a sunscreen suitable for a child it is important to take into account the following features:

  • Sun Protection Factor (SPF) - This describes the level of protection a sunscreen gives from ultraviolet (UV) B radiation (290-320 nm), the wavelength of light responsible for sunburn and known to cause skin cancer. The higher the SPF, the better the protection. An SPF of 30 or more is deemed ‘high’, blocking out 97 % of UVB radiation. Significantly, no sunscreen provides 100% protection from ultraviolet light, thus the need for additional protective measures.
  • Broad Spectrum - This refers to a sunscreen’s capacity to protect against other types of ultraviolet radiation, UVA (320-400 nm), which are known to cause damage to skin cells. The following ingredients are among those which provide broad spectrum protection: avobenzone, cinoxate, ecamsule, menthyl anthranilate, octyl methoxycinnamate, octyl salicylate, oxybenzone, sulisobenzone, titanium dioxide and zinc oxide.
  • Water resistance - Particularly important for children since they spend more time in the water, but also because it can indicate a higher level of abrasion resistance, which is useful given the vigorous and active nature of children.
  • The shelf life of the product - Sunscreens outside their expiry or “use-by” date may be rendered ineffective as their chemical components degrade over time.
  • Some babies and children may develop mild skin irritation in reaction to a particular sunscreen ingredient such as a preservative or perfume (severe allergic contact dermatitis is rare, but can occur). In these cases, an alternative brand with different ingredients can be applied. While allergic reaction to any chemical included in a sunscreen is possible, products with titanium dioxide or zinc oxide as their active ingredient are less likely to create such irritation. Sunscreens described as ‘fragrance free’ may also be more suitable for a child with sensitive skin.
  • Medium - While this will generally be reliant on your family’s lifestyle, it is worthwhile to mention that alcohol or gel based sunscreens may be more likely to be irritating or drying to sensitive skin. Conversely, these same products are usually easier to apply and are less aggravating for acne prone skin, common in teenagers.

Babies and toddlers

Infants aged 0-12 months should be kept out of the sun as much as possible. Premature babies in particular can have skin which is only partially developed and hence more permeable, this may make it more susceptible to UV damage. When solar exposure is unavoidable other precautions can be taken to prevent the need for frequent or large area sunscreen application. 

It is recommended that clothing is used as the primary method of solar protection. Parents or supervisors should ensure that infants and children wear broad-brimmed hats to cover the face and neck, closed toed shoes to protect the feet and light-weight clothing or wraps that are impermeable to sunlight to cover the body. Specific clothing with ultraviolet protection factor (UPF) ratings can be bought. UPF measures clothing’s ability to reflect, refract or absorb both UVA and UVB as a standardized, numerical rating. A UPF rating of 50 means that only 1/50th (or 2%) of the UV light can penetrate the fabric. Like sunscreen SPF, UPF ratings have been shown to be affected by water, so clothing should only form part of a photoprotective regime, particularly when swimming. Clothing colour has also been shown in research to affect the UPF of fabric, with darker colours (particularly dark blue) providing greater protection to skin than lighter colours, such as yellows and whites. Most government health agencies also recommend the use of wrap around, polarized sunglasses to protect eyes from sun damage.

Other provisions include:

  • Organising time outdoors to avoid the periods with strongest UV radiation, when the sun is at its apex. This generally occurs during the hours of 10am till 3pm (Australia), though varies greatly depending on time zone, season, latitude and daylight savings. The UV Index gives an indication of the daily levels of UV radiation; this can be found on the Australian Radiation Protection and Nuclear Safety Agency website.
  • Spending time in the shade where possible

Sunscreens undergo rigorous safety testing and there is no scientific evidence to indicate that sunscreen is unsafe for use on infants or young children. When well protected by these other methods, sunscreen need only be used occasionally on small areas of uncovered skin such as the face, hands, ears and neck.

Proper sunscreen application 

Despite awareness of the danger of exposure to UV radiation during childhood and its effects on the incidence of skin cancer later in life, little is known about the particular qualities of pediatric skin in relation to solar exposure. It has been theorized that this correlation comes from youthful skin being markedly susceptible to UV radiation, though the reasons for this are not clear. Therefore, the correct method of applying sunscreen, whilst relevant to all age groups, is particularly crucial for children. 

Sunscreen needs to be applied to clean, dry skin to allow for proper dermal absorption. The amount of sunscreen needed varies greatly depending on a child’s age and size. According to the COLIPA International guideline, 2 milligrams of sunscreen per square centimeter of skin is required to produce the level of protection described by the SPF value. For an average sized adult, this amounts to approximately one teaspoon of product on each arm, leg, back and torso, and half a teaspoon on the face and neck. A number of studies have shown that consumers apply much less sunscreen than is required, typically between 0.5 to 1.3 mg/cm2. Since application thickness has a significant effect on protection, most users achieve a mean value of only 20­-50% of that expected from the SPF on the product label. Therefore, paramount to protection is liberal, thorough coverage of all areas of skin exposed to sunlight, including areas that may become subsequently uncovered (i.e. by the movement of sleeves). 

While application on babies and young children is naturally undertaken by a responsible adult, a third party may also be required to assist older children and teenagers with difficult to reach areas, such as the back, to achieve complete coverage. The frequency of application differs for each sunscreen, but the general consensus is that reapplication every two hours is sufficient to maintain the SPF. Sunscreen should also be reapplied after swimming regardless of water resistance, as the abrasive action of drying off can remove the sunscreen. Meticulous attention should be paid to areas with extended contact to solar radiation (face, ears, neck, arms and legs). Sunscreen should be applied 30 minutes prior to exposure; this gives enough time for proper absorption into the skin and decreases the chance of it being wiped off. A second layer of sunscreen applied directly before sun exposure boosts the amount of filter chemicals in the skin and brings the SPF closer to its true value. An inadequate amount of sunscreen or imperfect distribution of the product often results in an SPF lower than that stated by the manufacturer. It is possible to compensate for this by cutting down the time your child spends in the sun or reapplying the sunscreen more often.

Teenagers 

While older children and teenagers are able to carry out much of their sun protection regime themselves, they often require education and/or encouragement from their adult carers. Their willingness to provide adequate safety for themselves may waver, along with the common challenge that sun protection may be deemed ‘uncool’ amongst their peer group. Surveys have shown that teenagers widely consider a tan as being both healthy and attractive. Studies show that despite their awareness of the dangers of UV exposure most teenagers do not practice sun safe behaviours. Another issue that is of concern among this age group is exposure to artificial UV sources such as sunbeds and sunlamps used for tanning. Discussing these ideas and attitudes with your child or teen as they arise may be helpful, as establishing safe sun care principles in youth can create healthy habits for life.

References

  • American Academy of Dermatology, 2010, Facts About Sunscreens, accessed 5th May 2010, <http://www.aad.org/media/background/factsheets/fact_sunscreen.htm>. 
  • Centers for Disease Control and Prevention, Don’t Get Burned! Summer Sun Safety Tips, Accessed Online 03 November 2016, https://www.cdc.gov/media/subtopic/matte/pdf/summer_burned.pdf
  • Australasian College of Dermatologists, 2001, A-Z of skin: Sunscreens, accessed 5th May 2010, <https://www.dermcoll.edu.au/atoz/sun-protection-sunscreens/>. 
  • Berneburg, M & Surber, C, 2009, ‘Children and sun protection’, British Journal of Dermatology, 161 (suppl. 3): 33-39. 
  • Cancer Council Australia, 2005, Position Statement: Sun protection and infants (0-12 months), accessed 5th May 2010, <http://www.cancer.org.au/policy/positionstatements/sunsmart/sunprotectionandinfants.htm>. 
  • Diffey, B, 2000, ‘Has the sun protection factor had its day?’, BMJ, 320: 176-177.
  • Godar, D.E et al., 2003, ‘UV doses of young adults’, Photochemistry and Photobiology, 77: 453-457.
  • Grange, G et al., 2010, ‘A survey of sun protection in schools in South Wales’, British Journal of Dermatology, 162: 452-468.
  • Huncharek, M & Kupelnick, B, 2002, ‘Use of topical sunscreens and the risk of malignant melanoma: a meta-analysis of 9067 patients from 11 case-control studies’, American Journal of Public Health, 92(7): 1173-1177.
  • Jhappan, C, Noonan, F.P & Merlino, G, 2003, ‘Ultraviolet radiation and cutaneous malignant melanoma’, Oncogene, 22: 3099-3112.
  • Marks, R, 1996, ‘The Use of Sunscreens in the Prevention of Skin Cancer’, Cancer Forum, 20: 211-215. 
  • Therapeutic Guidelines: Dermatology, Version 2, 2004, Therapeutic Guidelines Limited, North Melbourne.
  • Wester, R.C & Maibach, H, 1982, Neonatal Skin Structure and Function, Marcel Dekker, New York.

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