Consultant dermatologist and British Skin Foundation spokesperson Dr Emma Wedgeworth explains the Fitzpatrick scale, the three key facets of sun safety and types of rashes that children might develop after sun exposure
Skin cancer is the most prevalent type of cancer and a growing public health issue, with the incidence of all types of skin cancer – particularly melanoma, the most deadly form – increasing in recent years.1,2 A high proportion of skin cancer, particularly in fair-skinned individuals, is attributed to sun exposure3 and therefore sun safety is paramount in preventing and reducing the prevalence of skin malignancies. Epidemiological evidence has suggested that sunburn, and more specifically blistering sunburn, during childhood and adolescence can more than double the risk of melanoma later in life.4 Skin is particularly vulnerable to UV damage in childhood and this is therefore an ideal time to establish good sun-safe habits.
Dermatologists classify skin according to a numerical scale called the Fitzpatrick scale.5 This divides skin type according to its response to UV light as follows:
- Type 1: very fair skin. Never tans, always burns eg red hair, blonde hair, green or blue eyes, freckles.
- Type 2: fair skin. Mainly burns, tans poorly eg blonde hair, blue eyes, may freckle.
- Type 3: darker, white skin. Mainly tans, sometimes burns.
- Type 4: olive, light brown skin. Tans easily. Minimal burning eg Mediterranean skin.
- Type 5: brown skin. Tans easily, rarely burns eg patients of Indian origin.
- Type 6: dark brown. Black eg African origin. Almost never burns.
Although no skin type is immune to damage from the sun, it is important to realise that the risk of burning and of developing skin cancer is strongly correlated with our skin type.6 Skin type 1 and 2 have the highest risks of skin malignancies. Other risk factors for skin cancer include family history and increased number of naevi. While sun-safe behaviour is important for all, extreme caution should be taken in children with risk factors for skin cancer.
Types of UV light
To understand the effects of sun on the skin, it is helpful to be aware of the electromagnetic (light) spectrum. This is divided according to wavelength into ultraviolet (<400nm), visible (400-760nm), and infrared (>760nm). It is mainly ultraviolet (UV) radiation that has effects on the skin. UV is divided into UVA, UVB and UVC (which is filtered out by the ozone layer). UVB is more potent at causing erythema (redness) and damage to the outer layer of skin (epidermis). UVA is less potent but also reaches the middle layer of skin (dermis) and causes changes over time.
It’s important to realise that sun protection is not just about sun cream. There are three factors to sun safety:
- Covering up.
With the multitude of education, as well as high-quality sun protective clothing, hats and sunscreens available on the market, we should not be seeing regular episodes of sunburn in a child. Presentation to a healthcare professional with significant sunburn warrants a thorough medical and social history to ensure there are no underlying conditions (such as metabolic conditions) or any evidence of neglect.
For infants, sun avoidance is generally advised. Infants and young toddlers are not as adept at controlling their temperature as older children and adults, so they are at higher risk of heat stroke. Keep infants out of the direct sunlight at all times, but particularly between 11am and 3pm, because this is when UVB is at its highest intensity. However, both UVB and UVA are known to have detrimental effects on the skin.
The UVA component of sunlight can penetrate clear glass, so use mesh UV filters for the windows or UV window films. Use a parasol or canopy over a buggy to ensure protection. Babies should wear lightweight, protective clothing. Ultraviolet protection factor (UPF) denotes the fraction of UV rays allowed to pass through the material – UPF 50 means only 1/50th of the UV radiation reaching the material passes through it. Light-coloured cotton T-shirts are generally UPF 6, while thicker fabrics such as denim have very high UPFs. Specialist clothing such as swimsuits, hats and rash vests are designed to have UPF 50, while feeling cooler and being well tolerated in the heat. Clothing is one of the best available protective mechanisms against sun damage.
Sunscreens come in two types. Chemical sunscreens, which contain ingredients such as oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxateare, work by absorbing the sun’s rays so that UVB and UVA do not cause damage to the skin cells. These products are not suitable for regular use on children under six months.
Physical or mineral sunscreens, on the other hand, work by reflecting the sun’s rays off the skin. Physical sunscreens are mainly zinc oxide or titanium dioxide. They may be used in infants if necessary, but behavioural changes and covering the skin are the best options. When choosing a sunscreen for children, always make sure it has a high sun protection factor (SPF). This denotes the fraction of UVB rays allowed to penetrate the skin and only pertains to UVB protection. High factors, eg SPF 30-50, should be chosen for children. UVA protection is also needed and it’s important to ensure that products provide good broad-spectrum cover.
From ages six to 12 months, broad-spectrum chemical sunscreen may be used, although protective behaviour should be adhered to, as for infants. Optimum products are non-fragranced and high factor SPF 30-50. Apply sunscreen 15-20 minutes before going out into direct sunlight. It is very common to underestimate the amount of sunscreen needed.
The SPF labelling is based on an application of 2mg/cm2 under laboratory conditions. This amount is almost never reached by patients using it on a day-to-day basis.7 To compensate for this, it is important to use higher factor sunscreens and to ensure regular reapplication; every two to three hours or after swimming. Eyes should also be protected from the sunlight, so children should wear good-quality sunglasses in strong direct sunlight.
For older children, compliance can start to become a problem, because they dislike the feel and the inconvenience of regular sunscreen application. Distraction techniques can be useful, as well as different modes of application such as sticks for the face and nose. For very fair children, rash vests and wide-brimmed hats or legionnaire’s hats are useful during swimming or in stronger sunlight.
Limiting sun exposure can have a negative effect on vitamin D status. Vitamin D is essential in ensuring healthy bones and calcium metabolism. Minimal vitamin D is obtained through the diet, but the skin is well adapted to make vitamin D on exposure to high levels of UVB when the sun is high in the sky. Vitamin D supplements are also a useful way of obtaining optimum intake. It is not necessary to burn or tan the skin to make adequate amounts of vitamin D. For a fair-skinned person to synthesise large amounts of vitamin D takes around 15 minutes and they may burn after 30 minutes. Darker skins may need longer – up to two hours. For some individuals, it may be safer to obtain vitamin D in supplement form, rather than relying on sun exposure. It is advisable for all children under five to take vitamin D supplements (400-1000IU daily)8 and anyone at risk of vitamin D deficiency should also take supplements.
Sun-related rashes in children – diagnosis and management:
As mentioned before, sunburn should be a rare occurrence, particularly in childhood, but it is still seen more regularly than we would like. There isn’t usually any diagnostic uncertainty in sunburn. It typically develops a few hours after sun exposure and peaks at 12-24 hours. Sunburn presents as well defined erythema in sun-exposed areas. In more severe cases, oedema and blistering may be seen and in severe cases, systemic symptoms such as dehydration, chills and fevers may occur.
Children under the age of one with sunburn should be seen by a healthcare professional, along with any child who has severe sunburn or systemic symptoms. For milder sunburn, keep the child well hydrated and use analgesia if the skin is uncomfortable. Use a regular emollient cream or lotion (applied gently, without excessive rubbing) and keep the emollient in the fridge to enhance its cooling action. A mild topical steroid (such as 1% hydrocortisone) can also be used on the area of erythema for a few days until it settles.
As mentioned before, significant sunburn or multiple episodes in a child warrant a detailed medical and social history. Certain metabolic conditions, such as porphyria, can make a child extremely sensitive to the sun. In addition, some medications can make a child more sensitive to sunburn, such as antivirals, NSAIDs and some antibiotics.
Miliaria (prickly heat)
Miliaria (commonly known as prickly heat) is a reaction to heat, rather than sunlight. It occurs from obstruction of sweat glands and is common in children and particularly young babies. It typically presents as itchy red papules (small bumps) in the skin folds and over the body.
The main treatment for miliaria is to avoid overheating and sweating, by cooling the environment, avoiding excessive clothing and using light natural fibres instead of synthetic clothing. Light, lotion, refrigerated emollients and mild topical steroids may ease symptoms of itching.
Polymorphous light eruption (PLE)
This is rare, but can be seen in children as well as adults. It is thought to be a form of delayed-type hypersensitivity (allergy) to the sunlight.9 After 24-48 hours of sun exposure, patients present with a non-scarring itchy rash on exposed areas. The rash can be very heterogeneous, ranging from papules to small blisters to larger urticarial-like lesions. The rash may be worse in the early summer and then get better with repeated sun exposure or may only occur in very intense sunlight. Unlike sunburn, the rash doesn’t present as one area of uniform redness and often takes more time to develop. It won’t show pigmentation (tan) after resolving. In some children, particularly boys, this can present as itchy bumps on the top of the ears, which occur more frequently in springtime. Treatment for PLE is normally strict sun protection with good broad-spectrum UVA and high UVB protection.
Childhood sun exposure needs to be carefully regulated, particularly in children that have risk factors for later development of skin cancers. Healthcare professionals should be aware of sun-safe practices and of common sun-related rashes in children.
1 Muzic J, Schmitt A et al. Incidence and Trends of Basal Cell Carcinoma and Cutaneous Squamous Cell Carcinoma: A Population-Based Study in Olmsted County, Minnesota, 2000 to 2010. Mayo Clinic Proc 2017;92:890-8.
2 Reed et al. Increasing Incidence of Melanoma Among Young Adults: An Epidemiological Study in Olmsted County, Minnesota. Mayo Clinic Proc 2012;87:328-34.
3 Olsen C et al. Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use. Aust N Z J Public Health 2015;39:471-6.
4 Cust A et al. Early-life sun exposure and risk of melanoma before age 40 years. Cancer Causes Control 2011;22:885-97
5 Fitzpatrick Skin Type. dermnetnz.org/topics/skin-phototype/
6 Watts C. Clinical practice guidelines for identification, screening and follow-up of individuals at high risk of primary cutaneous melanoma: a systematic review. Br J Dermatol 2015;172:33-47.
7 Miksa S et al. Sunscreen sun protection factor claim based on in-vivo interlaboratory variability. Int J Cosmet Sci 2016;38:541-9.
8 Guide for vitamin D in childhood. Royal College of Paediatrics and Child Health. rcpch.ac.uk/system/files/protected/page/vitdguidancedraftspreads%20FINAL%20for%20website.pdf
9 Chantorn R, Lim H, Shwayder T. Photosensitivity disorders in children. Journal of the American Academy of Dermatology 2012;67:1093.e1-1093.e18