Sunburns are inflammations of the skin caused by excessive exposure to sunlight.
Among the different types of rays that reach the Earth from the sun, there are ultraviolet rays, or UV rays, which are able to stimulate the production of melanin in the skin, thus promoting tanning.
This effect is also caused by exposure to UV rays produced by sun lamps in gyms and beauty centers.
Prolonged exposure to UV rays, however, can have negative consequences on the skin. Naturally, the effects depend above all on the individual phototype, ie on the type and color of the skin; those with a dark complexion, naturally endowed with a higher concentration of melanin, are less sensitive to the effects of UV rays than those with fair skin, often accompanied by blond or red hair and blue eyes, characteristic of northern populations Europe. The skin color is generally divided into light, brown, black.
People with fair skin, despite the stimulation of UV rays, do not tan (phototype I), they tan little and with great difficulty (phototype II), or they tan at an average level (phototype III), but after an initial redness of the skin (erythema).
People with brown skin (phototypes IV and V) are able to tan more easily and without initial redness.
People with black skin (phototype VI) tan safely.
The initial redness of the skin (erythema) is caused by both type A and type B UV rays, with a shorter wavelength, and therefore more penetrating, and can also cause inflammatory processes in the long run. For this, they are called burning spectrum.
There is also a sunburn rating scale with its own precise unit of measurement. It is called Universal index of solar UV radiation or UVI, and indicates the minimum dose of UV rays capable of causing redness of the skin in a certain area following a single irradiation (erythematogenic dose). The minimum dose in phototypes I, II and III, typical of the Italian population, is calculated as the photoexposure of the skin for 20 minutes at noon in June for UVA radiation, and for 120 minutes for UVB radiation.
Another element to consider is that not all parts of the body are equally sensitive to the effects of UV rays; protruding parts, such as nose and ears, or more delicate ones, such as lips and eyes, are more sensitive. The same applies to the face and arms, which are normally more exposed to sunlight throughout the year and which are therefore more protected than the shoulders and torso. Furthermore, children and the elderly generally have more delicate skin than adults and, therefore, must expose themselves to UV rays by paying more attention. The time of day is also important: during the warmer seasons, when the sun is more perpendicular, the amount of UV rays that reach the skin is greater.
Another element that can dangerously increase the risk of getting burned is the presence of surfaces such as water, sand or snow which, reflecting the sun's rays, significantly increase skin absorption of UV rays.However, it must be remembered that the stimulation of melanin production by the body serves as a defensive barrier against possible damage caused by exposure to sunlight. This is what happens in populations in tropical areas.
How sunburn occurs and what are the risks
The most common sign of lower level sunburn, erythema, consists in "redness of the skin that occurs after a few hours of exposure to the sun. Prolonging the radiation, we pass to a real sunburn with swelling of the skin (edema) and intense itching; in the most severe forms there is also burning, severe pain and water bubbles in the affected areas, with more or less deep and widespread skin damage depending on the areas and the time of exposure.
In addition to local ailments (symptoms), general malaise, headache, fever, severe dehydration may appear. Prolonged exposure to UV rays can cause damage to the DNA of skin cells, leading to their death; this explains the reason why in the burnt areas there is always a process of exfoliation (peeling), ie the fall of dead epithelial cells. If the normal cellular self-repair mechanism is insufficient, in fact, it is necessary to wait for a complete replacement of the skin of the affected areas. It is a natural defense mechanism of the body, as well as the appearance of a tan in the parts subject to burns. The production of melanin, in fact, should be understood as a shield produced by the body against any subsequent exposure to the sun.
In cases of severe burns, the surviving cells can become cancerous cells and, over time, lead to skin cancers.Furthermore, it must be borne in mind that compared to the damage caused by a direct burn (open flame, infrared rays, microwaves, hot surfaces), the reaction of the skin to excessive exposure to ultraviolet rays occurs a few hours later than the damage inflicted. For this reason, the person has more difficulty in realizing its severity.In any case, redness and sunburn, except in rare cases, should be considered real burns of I and II degree.
It should also be emphasized that the damage caused to the skin by prolonged exposure to sunlight is not only the immediate type. The first long-term consequence for some categories of workers such as fishermen, sailors, beach operators, is the progressive aging of the skin, with dehydration and the formation of wrinkles, loss of elasticity, alterations in the cellular structure. As for the eyes, which are particularly sensitive to UV radiation, the risks are those of developing photokeratitis and cataracts. In some cases, melanomas and skin cancers can occur.
What to do in case of sunburn and when to see a doctor
First of all, avoid further exposure to sunlight, placing yourself in the shade or, better still, in a closed place.
If the redness (erythema) is not excessively severe and extensive, it is necessary to apply sponges of warm or cool water (never too cold) to relieve the burning and, subsequently, apply emollient and moisturizing creams on the affected parts.
If the burn level is significant, it is advisable to use an ointment containing 0.5% hydrocortisone but, if the affected areas are very extensive, it is good to use this drug only after consulting your doctor.
Products containing antihistamines should never be used, as they could cause allergic reactions due to exposure to sunlight.
To relieve pain due to erythema and edema or in the presence of water bubbles, it is possible to take a simple analgesic to be taken by mouth, such as those based on paracetamol or ibuprofen.
Also, since sunburn of all levels causes dehydration, you need to drink plenty of water, preferably at room temperature.
It is absolutely not necessary to cover the skin with bandages or other materials in order to protect it, because the skin needs to breathe and be hydrated to soothe the effect of sunburn.
As with blisters, water bubbles should not be broken, because this could cause bacterial infections or, in any case, slow down healing times; on the contrary, the best thing is to ensure that the liquid that has formed can over time be reabsorbed inside the skin itself.
In the most severe cases of sunstroke with erythema and skin lesions, headaches, chills, fever, nausea, vomiting may appear. This occurs above all in subjects with type I and II phototypes who can be affected even after short exposure to UV rays; in extreme cases, it can even lead to mental confusion and loss of consciousness.
When these symptoms (symptoms) last for more than two days, especially in the presence of fever above 38 ° with rapid heartbeat and increased respiratory rate, it is advisable to consult your doctor immediately.
When the intensity of sunburn is not so severe as to have to undergo medical treatment, it is possible to intervene on the affected areas with a series of natural remedies: ointments based on aloe vera, with strong antiseptic and healing properties, and ointments based on calendula, widely used in cases of skin lesions. Aloe also reduces the exfoliation effect of the skin.To make compresses and sponges, instead of simple fresh or slightly lukewarm water, you can use a chamomile infusion, possibly adding calendula essential oil, again for the soothing properties of these two flowers. In the case of minor burns, you can gently rub the skin with mint or eucalyptus essential oil, or both together, combined with water.
Prevent sunburn. Do's and Don'ts
For the most sensitive skin types (I, II, but also III) it is always advisable to expose yourself to the sun with adequate coverage (clothes, hats, dark glasses) to prevent redness (erythema), edema and sunburn. In addition, based on the skin type, season, time of day, place, amount of sunlight, certain precautions and gradual exposure to the sun's rays must be taken. Adequate nutrition can also help.
You also have to resist the temptation to get a tan quickly and at any cost, especially out of season by undergoing sun showers and lamps. Although the new generation ones are better shielded than in the past, it is always a massive dose of UV rays absorbed by the skin in a short time.
Conversely, natural and gradual exposure to the sun stimulates the body to produce higher doses of melanin, thus also allowing the skin to darken gradually and evenly.
Sunscreens are undoubtedly the first tool to prevent sunburn and should be used and chosen according to the individual phototype: types I, II and III, for example, need high protection creams, very high in the case of small children, the elderly and people with particularly delicate skin.
It should always be remembered that sun creams, once applied to the body and face, have a limited duration in time, even the so-called water resistant (waterproof); it is therefore good to apply the cream every three hours, especially after a prolonged bath or profuse sweating. The more you tan, the more you can reduce the level of sunscreen protection.
Attention should also be paid not to be fooled by windy days, which make the heat less perceived. The sensation of heat, in fact, is given by the infrared rays while the ultraviolet ones are cold and not felt. When the sky is cloudy, the UV rays hit the skin because they also pass through the clouds that spread them over a wide radius.
Since sand, like water, snow and all light surfaces, has a high reflective power which increases absorption by the skin, care must also be taken when standing under an umbrella. Furthermore, water acts as a magnifying glass, exposing the skin to a much greater risk of sunburn.
As for the period of exposure to the sun, the first hours of the day or late afternoon are recommended, when the sun's rays are more oblique and less hot; in this way the melanin has time to be stimulated adequately, avoiding burns.
The same is true for seasonality: the sun in May, August and September (unlike what is commonly believed) is less direct, because the rays are less perpendicular to the earth's surface; therefore, these are the best times to start sunbathing.
To a lesser extent, but still important, the locality affects: in Sicily the sun burns more than in Tuscany, as well as in the plains it is less dangerous than in the high mountains, where it reaches the skin with two thousand meters less atmospheric filter.
Proper nutrition can also help prevent sunburn.Consuming foods rich in vitamin C, vitamin E, beta-carotene, zinc, selenium, potassium decreases the risks; green light, therefore, to typically summer foods such as peaches, apricots, citrus fruits, kiwis, tomatoes, peppers, spinach, olive oil, wholemeal bread. Perhaps it is no coincidence that these foods are the basis of the Mediterranean diet.
In conclusion, to prevent sunburn you must avoid exposing the skin to the sun without protection for long periods, at inappropriate times and places. Where they occur, sunburn should not be underestimated in order not to allow the erythema to degenerate into greater and more serious damage, both immediate and future.
Pathak MA. Sunscreens and their use in the preventive treatment of sunlight-induced skin damage [Summary]. The Journal of Dermatologic Surgery and Oncology. 1987;13: 739-750
NHS. Skin cancer (non-melanoma) (English)
NHS. Actinic keratoses (solar keratoses) (English)
Sunlight, ultraviolet radiation, and the skin. National Institutes of Health Consensus Development Conference Statement. 1989; 7: 1-29
Krasnovidov VS, Lysak VF, Osipovich VK. Povrezhdeniia kozhi i glaz UF-izlucheniem solntsa [Damage to the skin and eyes from solar UV-radiation] [Summary]. Kosmicheskaia biologiia i aviakosmicheskaia meditsina. 1991;25: 46-50
National Toxicology Program. Ultraviolet-Radiation-Related Exposures. 14th Report on Carcinogens (RoC). 2016
Katiyar SK, Mantena SK, Meeran SM. Silymarin protects epidermal keratinocytes from ultraviolet radiation-induced apoptosis and DNA damage by nucleotide excision repair mechanism. PLoS One. 2011; 6: e21410