Rash from sun


Strong sunlight can cause skin rashes. Many people suffer rashes, especially in spring and at the beginning of summer, when the first strong rays of the sun hit their skin. In general, any changes to the skin caused by ultraviolet or visible rays of the sun are called Photodermatoses. This includes relatively harmless rashes as well as more serious skin disorders.

This is not a single clinical picture, but a collective term that includes various diseases. According to the ICD-10 (international classification system of diseases) the following diseases are grouped under the term "photodermatoses":

  • Phototoxic reaction to drugs
  • Photoallergic reaction to drugs
  • Phototoxic contact dermatitis
  • Uriticaria solaris
  • Polymorphic photodermatosis
  • Other specified acute skin changes from ultraviolet rays
  • Acute skin changes caused by ultraviolet rays, unspecified

The symptoms of the diseases are different. Skin rashes in the course of exposure to the sun usually mean acute sunburns (Solar dermatitis) or the polymorphic photodermatosiswhich is often, admittedly incorrectly, referred to as light allergy or sun allergy. However, there are also phototoxic or photoallergic dermatoses who also have skin rashes from the sun. Medicines or other substances can make the skin more sensitive to light and cause skin rashes.


The causes of rashes caused by the sun are very different. This is due to the fact that sun rays are whole various skin manifestations can lead to. In the following section, the most important causes and clinical pictures are briefly presented so that a distinction is possible.

  1. sunburn (Dermatitis solaris): One possible cause of a sun rash is the Solar dermatitis, which is popularly simply called sunburn is known. The sunburn is similar to one Burning of the skin first to second degree. It is radiation-induced damage to the upper skin cells (Epidermal cells). This creates a Redness and swelling of the skin with blistering. This usually heals without scars, but can also leave pale scars. The cause of sunburn is UV radiation from the sun.
  2. Polymorphic photodermatosis (Sun allergy): The polymorphic photodermatosis is the change in the skin, which is popularly usually called light or Sun allergy referred to as. However, this term is incorrect as it is not an allergic reaction of the skin. The cause of the polymorphic photodermatosis is unknown.
    Usually hours to days after the first contact with sunlight after the winter months, a rash that is characterized by a blotchy appearance. It comes to Redness and blistering. Also is a severe itching characteristic. However, the skin manifestations vary from patient to patient. It is interesting, however, that every patient receives a new one Photodermatosis has the same skin changes that he previously suffered.
    A hypothesis on the origin of the polymorphic photodermatosis is that when the body is exposed to UV radiation, antigens are created against which there is then a defense reaction.
  3. Photosensitivity: The term Photosensitivity denotes a abnormal sensitivity of the skin to light. It can have very different causes. The skill Medicines, substances but also metabolic diseases that make the skin vulnerable. It then reacts with even low levels of light or sunlight Skin rashes, redness, itching, burning sensation, paresthesia or sunburn. Photosensitivity occurs for example in illness Xeroderma pigmentosum on.
  4. Photoallergic dermatitis: The photoallergic dermatitis refers to a disease in which there is a allergic reaction of the skin comes. This is caused by the combination of UV (A) radiation and a specific substance that has previously sensitized the skin. Such a substance can, for example, a Drug or dye be.
    Also Fragrances or components of Sunscreen are common allergens. The skin symptoms are then limited to the areas of the skin exposed to light. At the same time, these skin areas must have had contact with the allergen. It show up Redness and papules, blistering occurs less often.
  5. Lupus erythematosus: Of the Lupus erythematosus is an autoimmune disease that is associated with an increased sensitivity of the skin to light. Typical skin manifestations occur, including the so-called Butterfly erythema of the face counts. This is called because of its typical shape. Of the Lupus erythematosus recruits complex clinical picture in which there is an involvement of other internal organs, such as the heart or the kidney. The cause is the production of antibodies against the body's own cell components.
  6. Rarer causes: There are a few more rare diseases that can lead to a rash from the sun. Here too, allergens and skin sensitization play a decisive role.
    An example of such a rarer sun rash is the Aquatic grass dermatitis. When the skin comes into contact with certain components of the plant and subsequent UV-A radiation from sunlight, a streaky to reticulate skin rash occurs. This reaches its maximum after 3 days with one Redness and blistering. Of the skin rash only shows up on the skin that came into contact with the plant. The rash heals after 2 to 4 weeks. However, over-pigmentation can remain on the skin for months, which are visible as darker areas.
    Another rare cause is that Berloque dermatitis, also Photodermatitis pigmentaria called. This is also a phototoxic dermatitis. It is triggered by plant substances, which are often found in perfumes, in combination with sunlight on the skin. Increased skin pigmentation is typical here.

More about this topic can be found Rash causes


The diagnosis of a sun rash should be made by a dermatologist. This can determine the cause of the rash through specific questions and other diagnostic tools. Important questions are addressed to the time the skin has been exposed to the sun, the type of rash, accompanying symptoms and the frequency of such symptoms. However, since there are different clinical pictures that can cause a rash, the diagnosis must of course be specially adapted.

As already discussed, the anamnese, the targeted questions. This is followed by an exact Examination of the skinso that the rash can be assessed in terms of its quantity and quality. In combination with the information requested, such as secondary symptoms, time of occurrence, duration of exposure to the sun's rays on the skin and the patient's history with regard to such rashes, a more detailed cause can often be narrowed down. E.g. a patient who has been in the sun for 7 hours and presents with a sore red rash is very likely to have sunburn.
However, a patient who is more likely to present with an itchy, blotchy rash after being in the sun for the first time after winter may be more likely to have one Polymorphic photodermatosis ("Sun allergy") suffer. In the latter case, diagnostic exposure to UV-A rays is also possible in order to provoke a rash and confirm the diagnosis. However, this is usually not necessary, as the examination and the patient discussion are clear.

Another important diagnostic tool is the exposed one Patch test, which is also called Photo patch test referred to as. This test is carried out as follows: first, the minimum erythema dose of the skin is determined by exposure to UV-A and UV-B radiation. This is a measure of the skin's tolerance to solar radiation. Then test substances are applied to both halves of the back.
These test substances are possible allergens. Then half of the back is irradiated with UV-A rays. If there is a rash on the irradiated side, the diagnosis is one allergic photodermatitis most likely. So it is a kind of allergy test.

More about this topic can be found Allergy diagnostics

Other accompanying symptoms

Probably the most impressive accompanying symptom of a rash from the sun is that itching. A severe itching is especially characteristic of the polymorphic photodermatosis, which is popularly referred to as "sun allergy". However, itching can also occur with sunburn (Solar dermatitis) occur. Typical of a sunburn is, in addition to the typical skin symptoms, how Redness and Swelling, a severe pain up to Paresthesia like one Numbness. With a large extent of the sunburn it can also lead to a general exhaustion and fever come.
Sometimes other primary diseases, such as a Lupus erythematosus or one Porphyria, an increased sensitivity of the skin to light, which can also lead to a rash caused by the sun. Then symptoms of the primary disease continue to appear in addition to the characteristic skin symptoms. At a Lupus erythematosus can for example Joint pain, Muscle aches, one anemia and general feeling of illness occur, to name a few symptoms.

Rash on the arms

In the case of polymorphic light dermatosis, severe itching can occur

A rash from the sun on the arms is particularly common, as these are one of the parts of the body that is particularly exposed to the sun. Furthermore, the shoulders, the face and the cleavage belong to it. One is particularly common on the arms polymorphic photodermatosis.
This rash, which occurs mainly in the course of the first more intense rays of sun after the winter months, is particularly evident in the Outside of the upper arms, in the cleavage or on the face. Redness, vesicles, nodules or weeping skin defects are typical. This can express itself very differently in every person. However, it is typical that the skin appearance is always the same on a person affected when he repeatedly on one polymorphic photodermatosis suffers. Another characteristic is a severe itching.

To prevent such a rash on the arms, this is recommended Wear tightly woven clothing. Unfortunately, since it is caused by UV-A rays, thin clothing is not enough to protect the skin as the UV rays simply penetrate it. Furthermore, a Sunscreen with a high sun protection factor (SPF 30 and higher) help to protect the skin.
In therapy, if necessary at all, ointments containing cortisone for use that are applied to the affected areas of the skin. In severe cases, a Getting used to light through UV radiation be performed.

Also the sunburn particularly likes to show up on the upper arms, as these areas of the skin are particularly often exposed to direct sun. With sunburn, redness and swelling, as well as pain and later itching, are in the foreground. Recommended for treatment cooling compresses. For local therapy for mild sunburn, there are corticosteroid-containing ointments (e.g. betamethasone) or gels that can be used externally.
However, a rash on the arms after being exposed to the sun can also occur in the context of, for example, a photoallergic dermatitis arise. Often there are allergens like Fragrances made from perfumes or Components of sunscreen products the cause of skin sensitization. After UV-A irradiation, skin rashes then occur, which typically present themselves with reddening and plaques. The rash is then strictly limited to the skin area that has been in contact with the allergen and sunlight.

Rash after taking antibiotics

There are some medicines that can cause skin photosensitization. This means that the skin becomes more sensitive to light. This can lead to phototoxic or photoallergic reactions when exposed to the sun. A precise distinction between these two is, however, often not possible. The result is rashes that are characterized by various skin symptoms such as redness, papules, pustules, vesicles or nodules. Itching can also be characteristic.
One group of drugs that can cause such reactions are the Antibiotics. However, not all antibiotics are equally capable of photosensitizing the skin. In particular the group of Tetracyclines, sun exposure can lead to rashes, itching and increased sensitivity of the skin. The so-called is particularly important here Doxycycline.
It is used, for example, for respiratory infections such as pneumonia. Another area of ​​application are infections of the ear, nose and throat area such as sinusitis or otitis media. Furthermore, infections of the urogenital and gastrointestinal area are also involved Doxycycline treated. The area of ​​application is therefore very large. When taking Tetracyclines should Refrain from sunbathing, going to the solarium and staying in the sun for a long time (e.g. gardening)to prevent such a rash.

In addition to the tetracyclines are also the so-called Gyrase inhibitors known to cause phototoxic reactions in the skin. The fluoroquinolones, which include various active ingredients, are among the gyrase inhibitors. They are often used in the treatment of urinary tract infections. These include, among other things Norfloxacin, Ciprofloxacin or Ofloxacin. More are fluoroquinolones Levofloxacin and Moxifloxacinthat also at Respiratory infections can be used. Skin should also not be exposed to the sun while taking these antibiotics, as this can lead to rashes and sunburns.

More about this topic can be found Rash after antibiotics


Therapy for a rash from the sun depends on the underlying cause. Since the sun's rays can cause various skin rashes, the therapeutic approaches also differ in some cases. The following section is intended to provide a compact overview of the most important sun rashes and their treatment options.

  1. sunburn / Solar dermatitis: In the case of a sunburn, it is recommended first of all, cooling and damp envelopes to be used on the affected skin areas. The cooling relieves inflammation and has a pain relieving effect. With a slight sunburn continue to come Gels, ointments and creamscontaining corticosteroids (e.g. Betamethasone), for use.
    One is recommended for more severe sunburns systemic therapy with anti-inflammatory and pain relieving agents such as Diclofenac. These are taken as tablets. If necessary, skin compresses with antiseptic additives can also be used.
    You can find more on this topic at Sunburn treatment
  2. Polymorphic photodermatosis: In the case of a polymorphic light dermatosis, first of all the consistent avoidance of sun exposure in the foreground as the rash is caused and sustained by UV-A radiation. If further exposure to the sun is avoided, however, it usually heals within a week without any consequences. If the skin is still exposed to the sun, consistent sun protection in the form of tightly woven clothing and sunscreen is important.
    Light habituation can also be carried out, which is applied 4 to 6 weeks prior to major exposure. For this purpose, a slowly increasing whole-body irradiation with UV-B rays is carried out. The point behind it is to quasi “harden” the skin and so on to prepare for the sun rays of spring and summer.
    In very severe cases, a so-called PUVA therapy considered. PUVA stands for Psoralen plus UV-A. Psoralen is a substance that sensitizes the skin to UV radiation. To do this, psoralen is applied to the skin and then irradiated with UV-A rays. Psoralen can also be taken as a tablet.
  3. In addition to the therapy options mentioned, local glucocorticoids can be used to treat fresh skin changes. The benefits of Antihistamines against the itching is controversial, so these are more likely used cautiously.
  4. Phototoxic / photoallergic dermatoses: In the foreground is one Avoidance of the triggering substances, for example. Medicines, cosmetics and the like, as well as a consistent sun protection. In the acute stage you can Glucocorticoids be used in the form of ointments and creams.
  5. Many botanicals act as Home remedies for a rashby soothing and moisturizing the skin.

Read more about this at: What to do if you have a rash


Skin rashes caused by the sun usually heal relatively quickly. However, this also depends on the type of rash. A slight sunburn, for example, shows its maximum 12 to 24 hours. It usually heals within a week without any consequences. However, if the sunburn is severe, healing may be delayed.
A "light allergy" (polymorphic photodermatosis), as it is popularly known, also heals in the vast majority of cases within a week.
However, this also depends on the attentiveness of the person concerned. If the skin is exposed to the sun again, healing will be delayed or the rash may even worsen. It is similar with one photoallergic or phototoxic dermatitis. The triggering substances as well as the sun should be avoided. In these conditions, the rash heals quickly. In rare cases there are longer courses.

Rash in child

Like adults, children can also experience rashes caused by sunlight. Basically it is the same clinical pictures that plague adults. Most common in children is sunburn. Children's skin is particularly sensitive and needs thorough care with sunscreen (SPF 30 or higher).
The symptoms are the same as in adults. There is redness, swelling, pain and itching. Severe sunburn can cause blisters and general fatigue and a fever.
Photoallergic and phototoxic skin reactions can also occur in children. If children are given new medication and they experience a sudden rash after exposure to the sun, an allergic reaction may be thought of and the attending physician should be made aware of this.
Read more on the subject at: Sun allergy in the child
Furthermore is a polymorphic photodermatosis possible for children (see above). A disease that mainly affects children under the age of 10 is Hydroa vacciniformia. It is a very rare, smallpox-like rash
In the acute stage, painful and itchy blisters form, which the children understandably scratch open. This can lead to scarring. Ointments containing cortisone, which can be applied to the affected skin areas, often help. In very severe cases, therapies with corticosteroid tablets are used.

More about this topic can be found Rash in children

Rash on baby

Babies are very sensitive to strong sunlight. Your skin must therefore be protected particularly well to avoid sunburn or the like. In general, babies should not be exposed to sunlight for too long and especially not unprotected.
A polymorphic photodermatosis ("Sun allergy") is less common in babies. Nevertheless, you shouldn't take it too seriously and protect the children well. If babies develop wheals and redness after sunbathing, it is quite possible that it is a photodermatosis. This usually heals in a week without any consequences. However, the sun should be avoided during this time.

More about this topic can be found Rash on baby