CHILDREN AND THE SUN by Dr David Atherton, Consultant Paediatric Dermatologist at Great Ormond Street Hospital

A to Z on protecting kids’ skin from the sun by Dr David Atherton, Consultant Paediatric Dermatologist at Great Ormond Street Hospital.

 

yellow sunshine

 

EFFECTS OF THE SUN ON THE SKIN

 

These effects can conveniently be subdivided into early and late.

 

Early effects

 

Sunburn

 

Sunburn is a reflection of lethal damage to epidermal cells, and to small blood vessels in the underlying dermis. The cardinal sign of sunburn is redness, but when severe this may be accompanied by blistering, due to the accumulation of fluid below the epidermis. There is generally a delay between UVR exposure and the appearance of sunburn of 3-5 hours, but the reaction may not reach its peak until 12-24 hours. It is principally UV-B that is responsible for sunburn. How much exposure is required depends on many factors including the degree of natural pigmentation of the skin.

 

 

If a child is sunburned, it can be useful to use a topical steroid to reduce inflammation. Research is under way to establish the value of antioxidants in green tea, for example, which may also be able to reduce the risk of sun damage leading to development of skin cancer. Children who have sunburn will also have increased loss of water through the damaged skin and require oral fluid replacement, particularly if blistering occurs.

 

Tanning

 

Tanning results from increased production of melanin in the melanocytes located in the epidermis. Tanning is largely a response to UV-B wavelengths. Due to the complexity of these processes, it takes about 72 hours for tanning to appear following UVR exposure.

 

Immunosuppressive effects

The skin has a powerful immune system, whose primary function is protection against skin infection by a variety of micro-organisms and against infestation by parasites. UVR has a powerful suppressive effect on this function, which is probably the reason that cold sores are not an uncommon complication of sun exposure.

 

Late effects

One might think that these are not issues with which we need to be particularly concerned when considering the UVR on children’s skin. However, it has been shown that the majority of our UVR exposure occurs in childhood, and that this is therefore when most of the skin damage occurs. It is the protective measures we take with our children that will count in their later adult lives; the measures we take ourselves as adults are of much less importance.

 

Ageing

Although some ageing takes place in the skin even in the absence of UVR exposure, it is estimated that about 90% of the ageing effects observed in the skin are the direct result of UVR exposure. These effects include wrinkling, dryness, mottled pigmentation and laxity. The wrinkling and laxity appear to result largely from damage to elastic fibres in the dermis.

 

Carcinogenesis

The commonest skin cancers are basal cell carcinoma and squamous carcinoma. The risk of these cancers correlates well with cumulative lifetime UVR exposure, particularly in those with lighter skin colour. Malignant melanoma is a more dangerous form of cancer, and one that is steadily becoming more common. While it is clear that UVR exposure is important, its precise relationship has been difficult to determine. It now appears likely though that the main provocative factor in malignant melanoma is high-level UVR exposure and sunburn in childhood. There is animal evidence that suggests that even a single sunburn experience may be enough to result in later development of malignant melanoma.

 

PROTECTION OF THE SKIN FROM UV RADIATION

 

Natural

The skin provides a range of natural defence mechanisms against damage by UVR. In general, those who start with naturally darker skin will tan faster than those with naturally light skin. Those with naturally more pigmented skin will be better protected against the harmful effects of UVR, and the lighter-skinned will be helped by getting a tan. However the benefit of natural pigmentation and of tanning is mostly expressed in terms of protection against sunburn. It appears that natural pigmentation or a tan provide less protection against photoageing, and one can clearly see severe photoageing in photographs of elderly Blacks and Orientals who have led an outdoor life. Furthermore, the process of getting of a tan by a lighter-skinned individual will involve a risk of sunburn and will certainly involve unavoidable photoageing and photocarcinogenic damage.

 

Artificial

The main aims of sun protective measures are prevention of sunburn reactions and prevention of cumulative long-term skin damage, as we have already discussed. Although the first thing that parents consider in relation to protection of their children is sunscreens, other measures are more effective and therefore more important.

 

Time of year, time of day and shade

Understanding the factors that determine the level of UVR exposure of the skin is the key to protection of children. Although it used to be said that one need not be concerned about the sun in the UK between November and the end of March, this is not now necessarily always the case, probably mainly because of damage to the upper atmospheric ozone layer in the last 50 years or so. Nevertheless, in general, the months April to October inclusive are the ones that matter, and the hours between 10am and 4pm, when the sun’s rays have to traverse the least amount of atmosphere to reach us. This means that we should schedule children’s outdoor activities outside these hours as far as possible in the months that matter. When this can be achieved, other protective measures will not be needed. It is when this can’t be achieved that we need to consider such measures.It is important to be aware that UVR intensity is greatly increased at altitude, even during the winter months. Clouds do reduce UVR intensity somewhat but it does penetrate cloud depending on thickness; also clouds scatter UVR so that shade is not as effective. Snow, water and sand reflect UVR, increasing exposure and also reducing the effectiveness of shade. Simple structural measures should be regarded as a priority for schools, such as the planting trees to provide shade in playgrounds. Parents need to consider such measures for their own gardens. Children need shade for areas of relatively static play, such as sand pits, which can be protected by a canopy.

 

Clothing and headwear

Clothing and headwear are other considerations that are in my view more important than sunscreen use. In general, clothing should cover arms and legs in the summer months. Choice of fabric makes a big difference. Dark colours protect better than lighter ones. In general, the tighter the weave the more protective the fabric will be. A good way to test this is to look at the light through the fabric and check how much penetrates. If you can see through clearly, the level of protection is not very good. A thin white T shirt probably only provides the equivalent of SPF2. It is also worth noting that wet clothing is less protective than dry clothing. For added softness for children’s clothing, it is advisable to use non-biological products such as Fairy Non Bio that have a mild fragrance and have been evaluated for skin safety. Fairy Non-Bio skin safety has been reviewed by Allergy UK and awarded their British Allergy Foundation Seal of Approval endorsement. Clothes washed in Fairy Non Bio have been shown by the manufacturer to be as gentle next to skin as clothes washed in water alone. A suitable fabric softener will minimise the friction of clothing; again it is best to choose products that have been thoroughly evaluated for skin safety like Fairy Fabric Softener.

 

Sunscreens

Sunscreens are skin applications that protect by reflecting and/or absorbing UVR. There is a bafflingly large choice available. There are 2 broad categories of agents in sunscreens: physical and chemical. Physical agents largely work by forming an opaque white barrier that reflects away UVR. Their main disadvantage is that they are usually visible as a white film that adults regard as unattractive; their whiteness will be more apparent the darker a child’s skin is naturally. Tinted versions are available, which can be more acceptable, particularly in darker skin types. Despite this problem they should be preferred for children because they are equally effective for UV-A and UV-B, because they are very much less likely to irritate the eyes and because their use avoids the child being exposed to chemical agents that are associated with a greater risk of adverse effects. Chemical agents work by absorbing UVR energy. Each chemical absorbs best at a particular wavelength. This means that even when several chemicals are used in combination, the full spectrum of UV wavelengths will not be dealt with as effectively as by physical agents. Chemical agents are generally not as effective in the UV-A wavelengths. The effectiveness of sunscreens is most commonly expressed as an SPF (sun protection factor) value. This value is the ratio between the doses of UVR required to produce minimal sunburn on skin with the sunscreen compared to unprotected skin. The SPF value gives a reasonable indication of the degree of protection against UV-B wavelengths but little information in respect of UV-A. No widely accepted measure of UV-A protection is yet available. It is also very important in practice to know whether a sunscreen preparation will remain effective when a child is playing with water, or swimming, or sweating. Sunscreens have been associated with a number of unwanted effects. The biggest problem has been allergic reactions to chemical agents, and sometimes to preservatives and other additives that these formulations may contain. However, allergic reactions seem to occur in no more than 2% of the population. Stinging sensations are not uncommon with some preparations, usually due to a content of potentially irritating substances such as alcohol or preservatives in children with particularly sensitive skin, principally those who are prone to eczema.

 

Getting the balance right

In the early 20th century, increased awareness of the role of sunlight in vitamin D synthesis led to outdoor activities and sun exposure being regarded as healthy. Previously a tan was regarded as a sign of lower social class, indicating outdoor work, but it was Coco Chanel who famously changed perceptions and made the suntan a fashion symbol. However, by the middle of the 20th century it was becoming clear that UVR was a cause of skin cancer, and the pendulum started to swing the other way. Now, with more evidence of a non-skin cancer-protective role for vitamin D, we are becoming concerned that we may have overdone protection against sun exposure. We are looking for a new balance and a consensus has not yet emerged.

 

However, for the time being it seems sensible to regard all the sun-protective measures I have listed, including sunscreen application to the face, as advisable for children in the UK (who will be in the sun for more than an hour during the peak UVR period of the day between April and October). One should choose a sunscreen having at least SPF15 which states that it has good UVA protection and is water-resistant. If a child is forced to be in the open for more than 2 hours at a high-risk time, the sunscreen should be re-applied reasonably frequently, depending on circumstances. What remains unclear is whether this level of protection will allow fully adequate vitamin D production, but even leaving hands uncovered without applying sunscreen should allow adequate vitamin D production with more or less daily exposure of around an hour. It is probably a good idea to provide an oral vitamin D supplement during the winter months, November to March inclusive.

 

Useful websites

www.sunsafetyforkids.org
www.sunsense.marinschools.org
www.skincancer.org
www.info.cancerresearchuk.org

 

THE AUTHOR:

Dr David J Atherton, Hon. Consultant in Paediatric Dermatology at Great Ormond Street Hospital for Children (London WC1N 3JH). Dr David Atherton currently sees patients privately at Great Ormond Street Hospital for Children, at the Cromwell Hospital in West London and at the Princess Margaret Hospital in Windsor.

 

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