THE SUN AND HUMANITY – A (POSITIVE) RELATIONSHIP?In recent years, it has become clear that regular exposure to sunlight and artificial light sources for tanning (artificial sunlight) can have harmful effects. Excessive exposure to ultraviolet (UV) light can cause premature skin aging and skin cancer.
However, there should be no anti-sunlight campaign. Without sunlight, the survival of plants, animals, and humans is impossible. Many people enjoy basking in the sun, and the sun has a positive effect on our mood. A (lightly) tan from the summer sun is therefore part of normal life and poses no unnecessary risks.
Vitamin D, which is necessary for bone formation, is formed under the influence of sunlight. Sunlight contains a broad spectrum of light rays, including UVB (short-wave UV light) and UVA (long-wave UV light). Artificial light sources for tanning contain primarily UVA light and no, or only a limited amount of, UVB light. People with sun-sensitive skin (who tan with difficulty or not at all, but are mainly red) have a greater risk of premature aging and skin cancer than people who tan easily or have naturally dark skin.HOW DO SUN PROBLEMS ARISE AND WHAT ARE THE PHENOMENA?I. Consequences of excessive exposure to (artificial) sunlight
The consequences of excessive exposure to (artificial) sunlight can be divided into acute and long-term consequences.
Acute Consequences
The acute consequence of excessive exposure to ultraviolet light is the sunburn reaction. The skin is red, swollen, and sensitive to touch and heat. In severe cases, blisters may occur. This reaction is mainly caused by short-wave ultraviolet light (UVB light). The redness begins after 3-5 hours.
Long-Term Consequences
The long-term consequences can be divided into premature skin aging and skin cancer.
A. Premature Skin Aging
Premature skin aging refers to a combination of the following characteristics:
1. Decreased elasticity (wrinkles);
2. Patchy discoloration with (pale yellow and/or sometimes white patches) excess and/or deficient pigmentation;
3. Dilated blood vessels.
These abnormalities are caused by UVB light and probably also by UVA light. Skin that has been excessively exposed to (artificial) sunlight is often dry, pale yellow in color and feels leathery. Wrinkles and small blood vessel dilation occur more and more, particularly on the face and neck.
B. Skin cancer
There are several forms of skin cancer . The three most important forms are mentioned below. Basal cell carcinoma is the most common (+ 80% of all skin cancers) and easily treatable form of skin cancer, which almost never metastasizes, but can grow locally.
Squamous cell carcinoma is a less common (+ 10% of all skin cancers) and sometimes serious form of skin cancer, because this form can metastasize over time.
The rough spots that can be caused by sunlight and are common in people who expose themselves excessively to sunlight are called actinic keratoses . These spots can sometimes be precursors of this form of skin cancer.
The relationship between these two forms of skin cancer (basal cell carcinoma and squamous cell carcinoma) and exposure to ultraviolet light (both UVB and UVA light) is considered (very) likely by many researchers .
Melanoma(malignant mole) is also a less common form of skin cancer that can metastasize. With early treatment, the prognosis for this form is also favorable. In particular, sunburn with blistering in childhood appears to have an unfavorable effect on sun-sensitive skin, meaning it can increase the risk of developing melanoma in adulthood. (See also the brochure " Moles ").
Photosensitivity
Photosensitivity occurs when the skin reacts abnormally to normal exposure to (artificial) sunlight. The best-known and most common condition is polymorphic light eruption (PLE), also known as sun allergy. However, there are other skin and internal diseases that can be associated with photosensitivity. The use of certain medications can also cause photosensitivity.
The most important symptoms are discussed below.
Polymorphic Light Eruption
The best-known and most common condition is Polymorphic Light Eruption (PLE) or Chronic Polymorphic Light Dermatosis (CPLD). Polymorphic means "occurring in various forms." PLE is more common in women than in men and often develops in people with fair skin. It usually begins in young adulthood and is likely caused by ultraviolet light, usually UVA light, but sometimes (also) UVB light. The most common skin lesions are very itchy, small bumps on light-exposed areas of the skin. The reactions can develop spontaneously at any age. Young adults often experience symptoms for the first time after a sun holiday where they suffered a sunburn. The lesions usually appear one day (sometimes five days!) after exposure. Without further exposure, healing occurs within 7 to 10 days. Symptoms generally subside during the summer, while they may reappear the following year. Apparently, a temporary habituation occurs.
Skin conditions that improve or worsen with sunlight
. Many skin conditions improve with light. Light therapy is an important treatment option for dermatologists for skin conditions such as psoriasis or some forms of eczema. However, some skin conditions are worsened by sunlight. A well-known example is Lupus Erythematosus (LE), a condition in which red and scaly "scarred" skin lesions can occur.
Medication use.
Photosensitivity reactions can be caused by medications.
The following are well-known examples:
- Antibiotics - tetracycline, nalidixic acid, sulfonamides.
- Diuretics (water pills) - thizide diuretics, furosemide
- Analgesics (painkillers) - benoxaprofen, ibuprofen
- Antidiabetics (medicines for diabetes) - sulfonylureas
- Phenothiazines (medicines against nausea) - chlorpromazine
Local agents for the skin
Local agents can also cause photosensitivity reactions, such as:
- Cosmetics
Examples include perfume ingredients such as methylcoumarin and musk ambrette.
Paraphenylenediamine (hair dye) is also used
. Therapeutic ointments and creams
are well-known examples include Solutio carbonis detergent (tar), Phenergan cream, Azaron (anti-itch), Unicura soap, and hexachlorophene.
Sunscreens:
If a skin condition develops despite using a sunscreen, it could be an allergic reaction to one of its ingredients. Examples include para-aminobenzoic acid (PABA) and benzophenones.
Contact with plants:
Plant-based substances (usually furocoumarins) from certain plant families cause a reaction through direct skin contact and simultaneous sunlight exposure. Irregular, striped red skin lesions with blisters then develop. The most common example is hogweed. Other plants that can cause these reactions include parsnip, angelica, celery, parsley, dill, and rue.
How is photosensitivity diagnosed?
By answering the following questions, it can be determined fairly accurately whether the reactions are caused by UVB or UVA light.
Do the skin reactions occur:
- even behind glass?
- even in the shade?
- even despite sunscreen?
- even during partly cloudy conditions?
Four "yes" means it is probably UVA light. Four "no" indicates UVB light.
The dermatologist can usually make the diagnosis, particularly polymorphic light eruption, based on the patient's history and the observed skin reactions. Occasionally, it is necessary to use light tests to determine whether UVA, UVB, or visible light is the cause of the skin reactions. It can also be investigated whether certain substances (cosmetics, medications, etc.) cause a hypersensitivity reaction in combination with light (photopatch tests). Furthermore, laboratory tests can be performed on blood, feces, urine, and/or a skin biopsy to rule out certain diseases.
WHAT IS THE TREATMENT AND WHAT CAN YOU DO YOURSELF?
Photosensitivity
Treatable causes of photosensitivity, such as discontinuing suspected medications, naturally come first. Specific treatments can then be initiated. In the case of polymorphic light eruption, gradually acclimating the skin to the sun in early summer or spring is sufficient. Sunscreens (see later) can be helpful in this regard. A photo-adaptation treatment by a dermatologist can also be administered. This involves exposing the skin to a special artificial light source 2 to 3 times a week for several weeks every winter/spring or before a vacation. In severe cases of photosensitivity, antimalarial drugs (pills) have been shown to have a beneficial effect.
The following points should be considered in the case of photosensitivity:
- avoid the sun, especially between 11:00 AM and 3:00 PM;
- wear loose, light-colored clothing with long sleeves and a wide-brimmed cap
; - wind is cooling; Be careful on the beach when it's windy.
Sitting or lying still ("baking") is worse than moving in the sun
. Wet skin is more sensitive to sunlight than dry skin
. Snow and sand reflect a lot of sunlight
. Ultraviolet light penetrates water somewhat; you can also burn underwater
. Despite cloud cover, (a lot of) ultraviolet light reaches the earth
. In the mountains, more sunlight reaches the earth.
To measure the effects of light on the skin, the Minimum Erythema (redness) Dose (MED) was developed. This is the dose of UV radiation required to actually cause the skin to redden. The protection factor of a sunscreen is defined as the ratio of the MED with the product on the skin to the MED without the product on the skin. The factor is usually indicated by the letters SPF (Sun Protection Factor). For the user, this means that with an SPF of 6, for example, they can stay in the sun six times longer before burning.
The tan that sunlight produces in the skin is caused by the pigment melanin. Melanin is a neutral filter and also absorbs UVB rays. However, it's a mistake to think that a tan offers a high level of protection against UV rays. A tan induced by UVA radiation ("tanning gun") on previously fair skin offers little protection against UVB burns.
Sunscreens have provided excellent protection against UVB light for many years, thus preventing sunburn. Recent developments have also made protection against UVA and visible light reasonably possible in recent years. This is crucial because protection against UVB and UVA light can reduce the long-term effects of sunlight exposure, such as premature aging. The risk of skin cancer can also likely be reduced by using effective sunscreens.
For photosensitive patients, sunscreens containing sunscreens against UVB, UVA, and visible light are often essential. Because sunscreen manufacturers frequently change the composition and name of their product lines, it is impossible to provide a list of "effective" products.
Other factors to consider when using sunscreens include:
- Inadequate or even counterproductive effectiveness can be caused by an irritant or (photo)allergic reaction to the product used.
Sunscreens are intended to protect the skin and not, as is often thought, to extend the time one can stay in the sun, and certainly not to achieve a better tan!
Preventing skin cancer:
The Dutch Health Council recommends limiting sunbathing, both in the natural sun and with artificial UV sources, to 100 MED per year to prevent skin cancer.
People on a sun holiday in Southern Europe can use this dose of 100 MED in three weeks. People who sunbathe moderately will receive approximately 20-40 MED during the summer.
The total dose from one tanning session of 10 exposures is approximately 10 MED. It is recommended to limit yourself to a maximum of five tanning sessions of 10 MED per year (see the brochure "Sensible Sunbathing" from the Netherlands Cancer Society/KWF). Using these examples, you can roughly estimate whether the amount of UV rays on your skin falls within this 100 MED.
Sunscreen ingredients:
1. UVB filters are: Cinnamates, camphor derivatives, para-aminobenzoic acid (PABA) and derivatives, benzophenones, salicylates.
2. UVA filters are: Debenzoylmethane derivatives, camphor derivatives.
3. Powders are: Titanium dioxide, zinc oxide, iron oxide. |
