What is sun allergy, what are sun allergy symptoms and how can you best deal with sun allergy? Sun allergy symptoms consist of red, often painful rashes on the skin exposed to (sun) light; small, itchy blisters and white blisters; flaky skin; swelling. The skin abnormalities that occur with sun allergy usually occur within 24 to 48 hours in areas of the skin that are exposed to the sun, such as the face and hands. It may also take a few days longer for the symptoms to appear and sometimes they occur almost immediately. Sun allergy can cause a lot of discomfort. Strictly speaking, treatment is not necessary. The rash disappears spontaneously after a few days to weeks and there are no residual symptoms. Over the summer, habituation occurs. If desired, the doctor can prescribe medication for sun allergy, especially if the itching is very bad. Sun allergy is also called ‘solar dermatitis’.
- What is sun allergy?
- polymorphic light eruption
- Sun allergy at a glance
- Causes of sun allergy
- Abnormal immunological response
- Abnormal response to UVA
- Hypersensitivity to various substances
- Symptoms of sun allergy
- Preferred places
- General features
- Abnormalities all over the body
- The severity of the complaints can vary greatly
- Examination and diagnosis
- Light tests
- Sun allergy treatment
- Different medicine
- Cream and ointment
- Light habituation in sun allergy
- Medication for sun allergy
- Avoid sunlight
- Sunscreen and special lamps
- What are the sun protection effects of different clothing fabrics?
- Prevention of sun allergy
Sun allergy is hypersensitivity of the skin to ultraviolet (sun) light / Source: Istock.com/LiudmylaSupynska
What is sun allergy?
Many people suffer from sun allergies. A sun allergy is when there is hypersensitivity of the skin to ultraviolet (sun) light, which is manifested in red spots and discomfort. It is an abnormal skin reaction that occurs after normal exposure to (sun) light. So light sources other than the sun can also cause sun allergy. Consider, for example, the light from a tanning bed, incandescent lamp or fluorescent tube. Sun allergy in itself is not dangerous.
polymorphic light eruption
The most common form of sun allergy is polymorphic light eruption (PMLE), which means ‘skin rash that occurs in different forms’ (polymorphic), under the influence of (sun) light (light eruption).
Sun allergy at a glance
Sun allergy is one of the most common skin conditions resulting from exposure to sunlight and indicates an acute reaction to the ultraviolet radiation in sunlight. Women suffer from it more often than men. It usually occurs between the ages of 20 and 40. Sun allergy is rare in children. Sun allergy is characterized by suddenly appearing red, swollen spots, blisters and sometimes eczema on parts of the skin that have been exposed to the sun. The affected skin itches and may cause a stinging sensation. The complaints can last for a few days, after which the symptoms disappear without leaving scars.
Causes of sun allergy
Abnormal immunological response
Sun allergy is caused by an abnormal immunological reaction. Sunlight exposure normally leads to suppression of the skin’s immune system. However, if you have a sun allergy, this suppression is changed or reduced, as a result of which the immune system actively responds to sunlight. A certain type of immune cells, neutrophils, behave differently in people with sun allergy than in healthy skin. In addition, regulatory T cells, important drivers of the immune system, also play a role in sun allergy.
Abnormal response to UVA
Sunlight consists of visible light and invisible ultraviolet light, which is responsible for skin tanning and sunburn. These are normal skin reactions that ultraviolet light can cause. Ultraviolet light or UV light is divided into (short-wave) UVB and (long-wave) UVA. With PMLE there is often an abnormal (= different) response to UVA. Today, ultraviolet light is considered the main trigger of the condition.
Hypersensitivity to various substances
Another possible cause of sun allergy can be hypersensitivity to various substances, including medications such as some antibiotics (tetracyclines), diuretics (an agent that promotes the excretion of water by the kidneys) and oral contraceptives. Furthermore, the use of certain cosmetics and perfumes can be a cause. Diseases such as lupus erythematosus or eczema can also trigger sun allergy.
It is estimated that sun allergy affects 10 to 20 percent of the European population, predominantly women. This condition occurs less frequently around the equator. The first symptoms often occur between the ages of 20 and 40, possibly a little later in men. The condition is mainly seasonal and returns when one is intensively exposed to sunlight, i.e. during every sunny spring.
Symptoms of sun allergy
The skin abnormalities that occur with sun allergy usually occur after 24 to 48 hours in parts of the skin that are exposed to the sun, such as the face, neck, backs of hands, forearms, elbows and lower legs. It may also take a few days longer for the symptoms to appear and sometimes they occur almost immediately. Your face (as well as your neck and hands) often remains out of harm’s way, because your face is often slowly exposed to sunlight and therefore habituation occurs.
The symptoms of sun allergy include:
- red, often painful rash on skin exposed to (sun) light;
- small, itchy blisters and blisters;
- flaky skin;
Abnormalities all over the body
The abnormalities do not have to be limited to the skin exposed to (sun)light, but can spread to other parts of the skin. It can manifest on your face, chest, abdomen, back, shoulders, arms, hands, legs and feet. Some people only suffer from itching without any skin abnormalities. The skin lesions heal within 7 to 10 days if the person is no longer exposed to sunlight. There are no residual symptoms. In other words: you get nothing out of it.
The severity of the complaints can vary greatly
The majority of people with sun allergy only suffer from it to a limited extent and can minimize the allergic reaction by slowly increasing their exposure to the sun throughout the year. In (very) serious cases, people are so oversensitive that they hardly go outside when the sun is shining.
General practitioner with patient who suffers from sun allergy / Source: Istock.com/monkeybusinessimages
Examination and diagnosis
The GP will make the diagnosis based on the external skin symptoms and the course of the complaints. This is more difficult if the rash has disappeared when the doctor is visited.
In order to find out whether the reactions in PMLE are provoked by UVA or UVB, the doctor will ask the person whether the skin reaction also occurs:
- behind glass;
- in the shadow;
- despite sun protection products;
- during light cloud cover.
If you say yes four times, it is probably UVA. If you say ‘no’ four times, it appears to be UVB. Your GP can refer you to a dermatologist for more serious forms of sun allergy.
Research by trainee dermatologist Ines Schornagel of the UMC Utrecht shows that in more than 85 percent of cases, the diagnosis of sun allergy can be made on the basis of the patient’s medical history (the so-called ‘anamnesis’). Light tests are only necessary in cases of doubt or to determine the severity of the condition. When a light test is performed, your skin is exposed to various wavelengths of the light spectrum for several consecutive days. A protocol of four test days is optimal. In order to provide adequate therapy advice, the skin must be exposed to both UV-A and UV-B.
Sun allergy treatment
If the reaction is caused by medication, for example, the doctor will look for an alternative if necessary.
Cream and ointment
Symptoms can be relieved using corticosteroid cream or ointment and an antihistamine. An antihistamine suppresses allergic reactions. Recently, a sun allergy spray has also become available: it immediately prevents an allergic reaction of the skin to sunlight.
Light habituation in sun allergy
Treatment for PMLE can consist of light habituation, i.e. gradual and measured exposure to the sun in the spring. This can also be done through light therapy, where the person is exposed to an artificial light source several times a week for a period of time.
Medication for sun allergy
In some cases, PMLE can be treated with medications, namely antimalarials. These drugs are prescribed against malaria, but can also be used for PMLE.
Furthermore, the person can control the reaction by avoiding sunlight as much as possible and covering the skin when going outside. Another suggestion is to use a sunscreen with a high sun protection factor (SPF). Before you go into the sun, you should apply this sunscreen thoroughly. Furthermore, one can wear sunglasses with ultraviolet light protection. Wear long pants, a long-sleeved shirt, and a wide-brimmed hat. Be aware of skin care products and medications that can trigger an allergic flare.
Over the summer, habituation will occur, which will reduce the symptoms.
Sunscreen for sun allergies / Source: Asiandelight/Shutterstock.com
Sunscreen and special lamps
Applying sunscreen with a very high sun factor especially for skin with an intolerance to sunlight, avoiding bright sun and wearing protective clothing provide the best protection against sun allergy. (Children with sun allergy need extra protection. Protection against UV radiation is in any case very important for babies and young children, such as toddlers, toddlers and preschoolers.) However, if this does not provide sufficient relief, getting used to the sun via special lamps can help. . In that case, it is advisable to start early. Your skin is carefully exposed artificially to UVA and UVB sunlight 2 to 3 times a week, so that your skin slowly gets used to it. This takes place in a cabin equipped with 100% UVA lamps and 100% UVB lamps. Ask your doctor or dermatologist for advice.
What are the sun protection effects of different clothing fabrics?
The sun protection effects of various clothing fabrics have been investigated, measured according to their SPF (Sun Protection Factor):
- a silk blouse has a sun protection effect corresponding to an SPF of 280;
- a cotton blouse has an SPF of 56;
- a jersey T-shirt fabric has an SPF of 32; and
- polyester blouses have an SPF ranging from 5 for an open weave (crepe) to 500 for a close weave (satin).
Prevention of sun allergy
Sun allergy can be prevented by taking a number of measures:
- Don’t expose your skin to the sun for too long
- Let your skin slowly get used to the sun in the spring by building up slowly
- avoid the sun when it is at its strongest (between 11am and 3pm).
- cover the skin with clothing and wear a cap or hat
- use a sunscreen with a high protection factor (30 or higher)
- Apply sunscreen thickly to the skin about fifteen minutes before going into the sun
- Apply sunscreen every 2 hours and after heavy sweating, exercise or swimming
In some people, sun allergy may become less severe over the years and even disappear completely.
- Robson J, Diffey BL. Textiles and sun protection. Photodermatol Photoimmunol Photomed. 1990 Feb; 7(1): 32-4.
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