The day is glorious, the sun is shining - who does not push it out into the light now? Our beauty ideal and the sense of body cult do the rest: Hungry for tan, masses of people deliberately expose themselves to UV radiation on such days. And thus undress otherwise covered, neglected by the sun body parts. Enjoy the pleasant warmth and look forward to the tanned result. But for many it looks completely different. Especially the first rays of the sun leave on the still winter-white skin in people with a predisposition for a sun allergy itchy eruptions with ugly redness, blisters and wheals. UV-A rays are to blame.
Sun allergy: causes
A sun allergy (polymorphic photodermatosis) is not a true allergy such as hay fever. In people with a sun allergy, the effects of UV-containing sun rays cause substances that cause allergy-like skin symptoms. These occur exclusively on the sun-exposed parts of the body such as neck, décolleté, upper arms and shoulders.
The sunlight contains ultraviolet light in different wavelengths. In most sun allergic persons, the longer-wave UV-A radiation, the so-called browning radiation, is blamed as the cause. The effect of UV-A radiation is associated with the formation of aggressive oxygen particles, which are to play a causal role in the sun allergy. By releasing the body's own messenger histamine, it then leads to an expansion of the skin vessels, which in turn causes heat, redness and itching.
The best protection is to avoid the sun
For the time being, substances that prevent the release of histamine - so-called antihistamines - help against the intense itching. These can also be taken for the prevention of sun allergy. They inhibit the allergic inflammatory response of the skin. Prevention is also possible with a slow habituation of the skin to the sun - thus a slow increase of the sunbath. Likewise through the intake of vitamin A precursors (beta-carotenoids).
The most effective protection, of course, is to avoid sunlight. If you are still exposed to the sun, you should apply sunscreen with a high SPF and protect yourself with light cotton clothing.
A second known disease, in whose emergence the sun plays a major role, is the Mallorca Acne, which was actually named after the most popular holiday island of the Germans. For a good reason, because in Majorca, the disease was first observed: Sunbathing tourists suffered in rows under acne-like skin changes and itching. Even today, especially sun-hungry globetrotters are plagued in the southern climes of Mallorca acne. Mainly affected are the face, neck and décolleté as well as the upper arm and the back.
In contrast to polymorphic light dermatosis, Mallorca Acne develops through an interaction between the UV light of the sun and the ingredients of the cosmetics. Mostly it is fatty substances in sun creams and body lotions, which in combination with the sun are responsible for the rash. A switch to fat and emulsifier-free sun cosmetics helps those affected to get rid of the Mallorca acne.
The photoallergic reaction is a true allergy because the immune system is involved. The most diverse substances - from fragrances in cosmetics to chemical light filters in sunscreens to medicines - combined with sunlight can lead to an allergic skin reaction. Itching, blisters, redness, oozing skin and crusting are among the many symptoms that often occur many hours after sunbathing.
Good to know: Only in people with allergic "predisposition" it comes to a photoallergic reaction. To differentiate this disease from a polymorphic photodermatosis is the task of the dermatologist.
In the phototoxic reaction, the skin is directly irritated by substances that can be "poisonous" under the influence of the sun's rays. Even skin contact with certain plants - such as bear claws or meadow grasses - can lead to reddening, burning itching or swelling in sensitive contemporaries. The symptoms are reminiscent of a severe sunburn. It is also possible, however, that substances in the body and sunlight can not tolerate each other. "Toxic" skin often responds to the combination of certain drugs and UV rays.
Tip: Anyone who has to take medication such as antibiotics or anti-diabetic drugs, rheumatism or high blood pressure should inquire before the holiday whether photoallergic or phototoxic reactions can occur. A look in the leaflet or a consultation in the pharmacy give information.