Complaints & connections · borters.ch
Dermatitis solaris
The redness peaks only the next day — and the protection factor applies only to an amount hardly anyone puts on.
Also known as: sunburn · UV damage · sun damage
Open in the tool — with search and all the links →This compilation is for information and replaces neither medical diagnosis nor treatment. If you have symptoms, see a doctor.
Sunburn is not a heat reaction but damage to the genetic material of skin cells caused by ultraviolet light. From that follows the first practical point: it is felt too late. The redness reaches its peak only twelve to twenty-four hours after the sun — so seeing nothing in the afternoon says nothing about how much has been taken. The second point concerns the amount of sunscreen: the printed factor applies to a layer considerably thicker than the one usually put on — for an adult roughly three tablespoons for the whole body and a good teaspoon for face and neck. Applying it thinner gives not half the effect but a good deal less. Reapplying does not make up for a missed amount; it tops up after two hours, after swimming and after towelling dry. Also underestimated are water, sand, snow and altitude, which strengthen the radiation, and clouds and window glass, which protect less than people think. And a series of common medicines makes the skin markedly more sensitive to light. Repeated sunburns, especially in childhood, count towards later.
For an adult about three tablespoons for the body and a well-filled teaspoon for face, ears and neck. Put it on twenty minutes before going out, renew after two hours and after every swim.
A t-shirt, a hat with a brim and the midday hours in the shade work more reliably than any cream, because they do not depend on how much was applied.
Anyone starting an antibiotic, a water tablet or an acne medicine asks once about light sensitivity. That saves a sunburn that would otherwise stay unexplained.
Lukewarm to cool compresses, a cool shower, then a light, moisturising lotion. Ice directly on the skin does further harm; blisters stay closed.
Burnt skin loses more fluid than one notices. That explains part of the weariness after a bad sunburn.
Repeated sunburns, especially in childhood, raise the later risk. That is no reason for fear, but one for a skin check at sensible intervals.
Apply the gel thinly to the reddened skin, several times a day, as long as it feels good.
Spread cold quark a finger thick on a cloth, apply, remove as soon as it warms or dries — usually after 20 to 30 minutes.
The redness appears two to six hours after the sun and peaks at twelve to twenty-four hours — which is why you cannot see on the beach how much you already have. Sunburn with blisters heals in one to two weeks. Sunscreen needs two milligrams per square centimetre to reach the stated factor; what is usually applied is a quarter to a half of that, which brings the factor down to roughly its square root.
After sunburn, no treatment can undo the damage — the damage in the skin cells’ genetic material happened in the first minutes. Anti-inflammatories in the first six to eight hours damp redness and pain; after that they do less. Cool compresses and moisturising lotions ease it. Cortisone cream brings little in comparisons. After blisters the skin heals in one to two weeks; the mark afterwards takes months.
The delayed redness is why so many sunburns happen at all. How long one was in the sun says more than what one saw there.
A large part of UV comes through thin cloud, and water, pale sand and snow reflect it back as well. At altitude the radiation rises noticeably with every thousand metres.
Ears, back of the neck, tops of the feet, lips, the parting of the hair and the strip under a shoulder strap. They are the most reliably missed and the most reliably red.
Some antibiotics, water tablets, anti-inflammatory painkillers, St John’s wort and acne medicines belong here. The skin then burns at an amount of sun that would otherwise have done nothing.
Extensive blistering, fever, nausea or confusion go beyond an ordinary sunburn. In small children the threshold is lower than in adults.
The value that describes the other side of the trade-off. Consistent sun protection can lower the level — the answer to that is the measurement and, if needed, a supplement, not more sun without protection.
Taken in larger amounts over 10–12 weeks the time to redness rises measurably — by roughly a factor of 1.5 to 2. That corresponds to sun factor 2, not 30: not enough as protection. In smokers, sustained high doses were linked with more lung cancer in large trials.
4–6 mg a day over 9–10 weeks also lengthened the time to redness in small studies. The same placing: a small addition from inside, no replacement for shade, clothing and cream.
Taken together with vitamin E over weeks a slight shift of the redness threshold was measured — alone barely. On sunburn that has already happened neither acts.
UV light releases this signal in the skin itself, and the pigment cells then make melanin. The tan appears only after two to three days — it is the answer to damage, not the protection against it.
The precursor forms in the skin under UVB — the same radiation that causes sunburn. The need is covered after a few minutes; everything beyond that brings no more vitamin D, only damage.
Supportive, not protective.
The red oil from the flowers is the traditional use for burns — but only once the skin has cooled. And note: St John’s wort makes skin more light-sensitive, the red oil does not belong in the sun.
Set cold, as a compress. The mucilage lays over the irritated skin; the coolness is the larger part of the effect.
The best-known application of all — but only once the skin has cooled, and diluted in a gel. Oil on freshly burnt skin holds the heat in.
The blue oil with chamazulene, traditionally for irritated skin. Anyone who reacts to daisy-family plants leaves it out.