Everybody knows about sunburn - and the measures against it. But while one can avoid this direct effect of the sun's rays on the skin, countermeasures in a "sun allergy" are more difficult. Already every 10th German suffers from this hypersensitivity to the sun. Nevertheless, so that the joy of the summer is not clouded, sun allergies should prepare accordingly. How it works, explains Prof. Dr. med. Eberhard Paul, owner of a dermatological practice in Nuremberg.
The skin of more and more people is allergic to the sun. Is there an explanation for this?
Prof. Paul: To answer the question exactly, one must first distinguish between the different types of sun allergy. We generously deal with the term "allergy" without usually knowing in detail the mechanism of the hypersensitivity reaction. The phototoxic reactions without real allergic mechanism are certainly decreasing. These are caused by the combination of certain light-sensitizing substances with UV light - this includes, for example, Beloque dermatitis, which can also be triggered by perfume oils. Patient education was successful here.
Another large group is the so-called Mallorca acne, which is most likely triggered by certain components in sun creams or skin creams and UVA. The Mallorca acne can also be caused by UVA tanning in solariums.
The largest group of sun allergies, the " polymorphic photodermatosis" has been known since 1878, but is on the increase. More women than men are affected and the disease usually begins in young adults. Why this kind of light allergy increases is not known exactly.
The most severe form is the " sun urticaria" - a sunlight-induced form of hives, which is extremely rare but can lead to life-threatening shock with cardiovascular failure. The victims must go to the hospital immediately.
How do you recognize a sun allergy?
Typically, the lesions do not occur immediately during exposure to the sun but several hours to two days thereafter. The name "polymorphic", ie "diverse" skin disease shows that the appearance is not always the same. The rashes vary from patient to patient and may range from pinhead to pea-sized blisters to red nodules. They can be accompanied by excruciating itching, which does not diminish at night.
Can one prevent the sun allergy?
As already indicated, a meaningful prophylaxis is difficult because the causes are not known exactly. Mallorca acne is very successful when emulsifier-free sunscreens are used. It becomes more difficult in polymorphic light dermatosis. What looks different in different patients also suggests very different preventive measures. For all, however: Slowly get used to the sun and consistent sunscreen. Here are meant primarily suitable clothing and sunscreen with UVA and UVB protection.
As consistent protection against UVA radiation is particularly important for sun allergic patients, branded products should be used which, for B. in the pharmacy to buy. Cheap sunscreens often protect well only in the UVB range, while the UVA protection remains inadequate. This has been shown by studies at the University of Tübingen.
Which ingredients should a sunscreen contain for allergy sufferers?
It is beneficial if the sunscreens additionally antioxidants such. B. Vitamin E included.
Which possibilities of medical prophylaxis are there?
In some people, prophylactic calcium helps a few weeks before expected sun exposure very well, but not at all. The use of beta-carotene, which should be taken 30 mg a day, is similar. Some swear by it, others only benefit a little. According to studies from the US, smokers should not take beta-carotene as this may increase the risk of cancer.
Some sun allergic people use sunbeds to get used to the sun. What is to be considered?
In principle, by visiting the solarium prevention, in the sense of a kind of hardening against sun allergy, are operated. Prerequisite, however, is the slow increase in the dose, ie the length of stay on the tanning bed. At the beginning 5 minutes can be enough and 15 minutes should not be exceeded. For prevention, only those benches are suitable that emit UVA and UVB rays, since the polymorphic light dermatosis is triggered by both types of radiation. In addition, all cosmetics and skin care products must be removed before sunbathing.
By a sensible approach to the natural sun, however, one can get used to the skin also to the UV radiation. Patients who suffer from severe sun allergy with severe skin lesions should undergo hardening under the dermatologist's control, where the skin is progressively exposed to increasing levels of UV exposure, which is very time-consuming and should only be used in severe cases Use come.
If, despite all precautions, how can you treat the sun allergy?
In rashes and inflammation of the skin itching often occurs first. By using antihistamines as gels or tablets you can prevent worse at the beginning. If severe skin changes have developed, the walk to the dermatologist is inevitable. Corstison ointments or tablets bring rapid relief. Since the cortisone must be given only a short time, no skin damage or serious side effects are to be expected.
What should be considered when skincare after the sun?
Creams with antioxidants, such as vitamin E are cheap, but you can not expect an allergy prevention because you can not block strong reactions with it. Nevertheless, so-called after-sun preparations, or lotions with vitamins A and E and the skin-soothing agent panthenol may have a soothing effect on mild sunburns.