The day is glorious, the sun laughs – who is not now driven out into the brightness. Our ideal of beauty and the sense of body cult do the rest: Hungry for a tan, crowds of people deliberately expose themselves to UV radiation on such days. And so they also undress parts of their bodies that are otherwise covered and neglected by the sun. One enjoys the pleasant warmth and looks forward to the tanned result. But for many people it looks quite different. Especially the first rays of the sun leave behind itchy rashes with ugly redness, blisters and wheals on the still winter-white skin of people with a predisposition to sun allergy. UV-A rays are to blame.
Sun allergy: causes
A sun allergy (polymorphous light dermatosis) is not a true allergy like hay fever. In people with a sun allergy, the effects of the sun’s UV rays alone produce substances that cause allergy-like skin symptoms. These occur exclusively on the parts of the body exposed to the sun, such as the neck, décolleté, upper arms and shoulders. Sunlight contains ultraviolet light in various wavelengths. In most sun allergy sufferers, the longer wavelength UV-A radiation, known as tanning radiation, is blamed as the cause. Exposure to UV-A radiation is associated with the formation of aggressive oxygen particles, which are thought to play a causative role in sun allergy. The release of the endogenous messenger histamine then causes dilation of the skin vessels, which in turn causes warmth, redness and itching.
The best protection is to avoid the sun
For now, substances that prevent the release of histamine – so-called antihistamines – help against severe itching. These can also be taken to prevent sun allergy. They inhibit the allergic inflammatory reaction of the skin. Prevention can also be achieved by slowly accustoming the skin to the sun – i.e. slowly increasing the amount of sunbathing. Likewise by taking vitamin A precursors (beta-carotenoids). The most effective protection, however, is of course to avoid sunlight. If you are nevertheless exposed to the sun, you should apply sunscreen with a high sun protection factor and protect yourself with light cotton clothing.
Mallorca acne
A second well-known clinical picture, in the development of which the sun plays a major role, is Mallorca acne, which was actually named after the most popular vacation island of the Germans. For good reason, because it was on Mallorca that the disease was first observed: Sunbathing vacationers suffered in rows from acne-like skin changes and itching. Even today, sun-hungry globetrotters in southern climes in particular are plagued by Mallorca acne. The face, neck and décolleté as well as the upper arm and back are particularly affected. In contrast to polymorphous light dermatosis, Majorca acne is caused by an interaction between the UV light of the sun and the ingredients of cosmetics. In most cases, it is fatty substances in sunscreens and body lotions that, in combination with the sun, are responsible for the rash. Switching to sun cosmetics free of fats and emulsifiers will help the affected person get rid of Mallorca acne.
Photoallergic reaction
Photoallergic reaction is a real allergy, because it involves the immune system. A wide variety of substances – from fragrances in cosmetics to chemical light filters in sunscreen to medications – can combine with sunlight to cause an allergic skin reaction. Itching, blisters, redness, weeping skin areas and crusting are among the many symptoms that often appear many hours after sunbathing. Good to know: Only in people with an allergic “predisposition” does a photoallergic reaction occur. To distinguish this disease from a polymorphous light dermatosis is the task of the dermatologist.
Phototoxic reaction
In phototoxic reaction, the skin is directly irritated by substances that can have a “toxic” effect when exposed to sunlight. Even skin contact with certain plants – for example, hogweed or meadow grass – can cause reddening of the skin, burning itching or swelling in sensitive contemporaries. The symptoms are reminiscent of a severe sunburn. However, it is also possible that substances in the body and sunlight do not get along.”Toxic” skin often reacts to the combination of certain medications and UV rays. Tip: Anyone who has to take medications such as antibiotics or drugs for diabetes, rheumatism or high blood pressure should find out before their vacation whether photoallergic or phototoxic reactions can occur. A look at the package insert or a consultation at the pharmacy will provide information.
