Sun allergy is the popular term with which a set of symptoms derived from various skin diseases is described. They are characterized mainly by redness and itching of the skin , after a direct exposure to sunlight.
The most frequent form of manifestation is the luminous polymorphous eruption, also called “solar poisoning”. Often, people who suffer from it are forced to take preventive measures to mitigate the harmful effects of sun exposure. However, sometimes these measures are insufficient so it is necessary to resort to a treatment to counteract the symptoms.
Causes of sun allergy
The exact cause of sun allergy is unknown, it is not known with certainty why some people are more sensitive to the sun’s rays than others. It is known that the symptoms tend to appear as a consequence of a prolonged exposure to ultraviolet rays.
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- Race. Although anyone can be allergic to the sun, it is more frequent in certain races.
- Exposure to certain substances. In some cases the allergy symptoms are triggered when the skin is exposed to some substances (for example, perfumes or disinfectants) and then to sunlight.
- Take certain medications The consumption of certain medications increases the sensitivity of the skin to the sun. Among them: antibiotics with tetracycline , drugs derived from sulfonamides and some analgesics, such as ketoprofen.
- Diseases of the skin People with dermatitis have a higher risk of suffering from sun allergies.
- Family history of sun allergy.
- Antioxidants and skin oxidants. An imbalance between oxidants and antioxidants in skin cells can trigger this problem.
Symptoms of sun allergy
The symptoms may vary in each person depending on what triggers the allergy. In general, there are discomforts such as:
- Redness of the skin
- Itching or burning
- Peeling or scabs on the surface of the skin
- Blisters or urticaria
- Ulcers of different sizes
It should be mentioned that these symptoms do not appear immediately. It may take several hours, even days, until the symptoms of sun allergy begin to manifest. The areas that tend to be most affected are the most exposed:
Upon suspicion of a solar allergy, the doctor will start the diagnosis with a review of the patient’s medical history. It is very important to know how and at what time symptoms began to manifest. To avoid diagnostic errors it is important to rule out:
When the diagnosis is not conclusive, more exhaustive analyzes can be carried out:
- Analysis of exposure to ultraviolet radiation. It is used to see how the skin reacts at different wavelengths of ultraviolet radiation.
- Photoparche test. Shows if the cause of sun allergy is a substance applied to the skin before exposure.
- Blood tests and skin samples. They are performed in case of suspected undiagnosed disorder.
The choice of treatment varies depending on the type of sun allergy. In milder cases, avoiding the sun for a few days is enough to combat the symptoms.
Sun protection is the most important preventive measure to avoid the symptoms of this allergy. It is best to avoid prolonged exposure to sunlight. Among other preventive measures we find:
- Use sunscreen
- Wear clothing that protects the skin from the sun
- Wear sunglasses
- Hydrate the skin
- Avoid the use of medications that produce sensitivity to light
- Avoid the use of irritating chemicals
The following drugs can be used to relieve pain and redness :
- Apply creams with corticosteroids (such as hydrocortisone).
- Use antihistamines to relieve itching.
- Pills that contain corticosteroids, such as prednisone (only in cases of severe allergies)
- In extreme cases, immunosuppressants such as cyclosporine or azathioprine can be used.
If the sun allergy tends to be chronic, the doctor may suggest phototherapy, a treatment that helps achieve a progressive adaptation of the skin to the sun. For this, a special ultraviolet light lamp is used. The procedure is performed a few times a week and can be used to prevent allergies.
- Gruber-Wackernagel A, Byrne SN, Wolf P. Polymorphous light eruption: clinical aspects and pathogenesis. Dermatol Clin . 2014; 32 (3): 315-334. PMID: 24891054
- Patterson JW. Reactions to physical agents. In: Patterson JW, ed. Weedon’s Skin Pathology. 4th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2016: chap 21.