With the warming of the weather, sun allergies began to show themselves. Curious questions about sun allergy, which occurs as a result of the body's hypersensitivity to sun rays, Istanbul Allergy Founder, Allergy and Asthma Association President Prof. Dr. Ahmet Akcay replied.
What is sun allergy?
Sun allergy is an extreme sensitivity of our skin to the sun's rays and occurs due to exposure of the skin to sunlight. It is also known as solar urticaria or sun-induced hives. It manifests itself with attacks of hives in the form of recurrent, itchy redness, edema, and swelling on sun-exposed areas of the skin. Although it is generally seen as a mild allergy, when it is excessive, it can cause problems, limit our daily activities and negatively affect our quality of life.
What is the incidence of sun allergy?
Sun allergy is a rare type of hives. It accounts for less than 0,5 percent of all hives cases. The disease usually begins in the young (mean age 35), but can also be seen in newborns or older people. It is more common in women. Slightly higher incidence in atopic people who are prone to allergies 16% chance of coexisting solar urticaria with other types of chronic urticaria
How does sun allergy develop?
How sun allergy develops is not fully understood. It is an immediate hypersensitivity reaction that occurs after sun exposure, which may be IgE-mediated. One hypothesis put forward in the development of solar urticaria is as follows: “Sun rays activate an endogenous substance called chromophore, which can be found in serum or on our skin, turning it into an immunologically active photo-allergen. This then triggers the release of chemical substances from the allergy-causing mast cells, causing hives lesions.” Irradiated injection of the own serum of a person with sun allergy was also found to be consistent with this hypothesis, since it also causes allergies in the skin.
What are the triggers of sun allergy?
Sometimes, solar urticaria is triggered by certain medications. Some cholesterol-lowering drugs (such as Atorvastatin), some drugs used as antipsychotics (chlorpromazine), some antibiotics (such as tetracycline), or birth control pills can trigger sun allergy.
Exposure to sunlight after the use of perfumes, disinfectants, dyes or other chemicals can also cause sun allergy.
What are the symptoms of sun allergy?
A few minutes after exposure to sunlight, on sun-exposed areas:
- Symptoms are seen in the form of edematous blisters.
- Sun allergy can also develop in areas covered with thin, white clothing that allow the sun's rays to reach the underlying skin. Allergy can also occur around the eyes or on the lips.
- Skin under clothing usually reacts more severely to sun exposure. The face and hands are more tolerant as they are frequently exposed to the sun.
- Serious allergy symptoms such as nausea, wheezing, shortness of breath or fainting may also occur, especially if large areas of the skin are exposed to sunlight for a long time. However, allergic shock rarely develops, even with severe allergy symptoms.
When do the symptoms go away?
Skin manifestations begin to improve within one hour of cessation of sun exposure in 75 percent of cases and resolve completely within 24 hours. The severity and duration of symptoms can also vary with the intensity of the light.
How is it diagnosed?
The information obtained from the patient is very important in the diagnosis of sun allergy. It is important to have temporary hives that occur a few minutes after exposure to sunlight. Examination findings are normal when not exposed to the sun. The clinical findings are important in the diagnosis of solar urticaria, and the diagnosis can be confirmed by phototesting. The phototest looks at how and at what dose your skin reacts to UV light from a sun lamp of different wavelengths. The wavelength to which your skin reacts can help identify your particular sun allergy.
Photopatch testing may be useful to rule out drug-induced photosensitivity or photocontact dermatitis. The patch test, called photopatch, involves putting different substances known to trigger allergies on your skin, waiting a day, and then exposing your skin to UV radiation from a sun lamp. If your skin reacts to a certain substance, it may be what triggers solar urticaria.
There are some diseases that show symptoms of sun allergy. These
- Polymorphous light eruption,
- lupus erythematosus,
- drug-induced photosensitivity,
- Includes photo contact dermatitis.
How is sun allergy treated?
There are no guidelines for the treatment of solar urticaria. Different treatments have been used with varying success. Avoiding sun exposure using broad-spectrum sunscreens and dark clothing is logically recommended, as well as sun protection.
Antihistamines are the most commonly used drug as drug therapy. They can often provide relief, but usually require higher doses. Antihistamines have no effect on the rash in solar urticaria. Lotions can be used to relieve redness and burning.
Phototherapy (UVA, UVB, visible light) and photochemotherapy (PUVA) can be used to improve tolerance to sunlight. This tolerance development process should be based on the spectrum of action and the minimum urticaria dose. PUVA appears to provide a longer lasting response than phototherapy alone.
Does solar urticaria get better?
Solar urticaria is a mysterious disease that is not fully understood. Although the diagnosis is simple, the treatment is difficult. Solar urticaria usually develops in the thirties and becomes a chronic disease. Not all patients improve with treatment.
The probability of spontaneous recovery was estimated at 5 percent at 15 years after the onset of sun allergy and 10 percent after 25 years. In general, patients with severe urticaria are unlikely to improve. Many patients are confined indoors and have poor quality of life.
What happens if it is not treated?
Since solar urticaria is thought to be caused by a type 1 hypersensitivity reaction, severe episodes of solar urticaria can lead to fainting spells, shortness of breath, and even severe allergy symptoms.
Ways to avoid sun allergy
- Limit your sun exposure and stay out of the sun, especially between 10:00 and 16:00 when the sun is strongest.
- If your rash is related to a certain medication, contact your allergist.
- Wear closely woven clothing with maximum protection, such as long sleeves, long pants or long skirts.
- Consider wearing clothing with a UPF protection factor of over 40, which blocks the UV protection factor better than sunscreens.
- Apply a broad-spectrum sunscreen to exposed skin and reapply regularly.
- Wear sunglasses and a wide-brimmed hat when outside; use a parasol.
As a result:
- Sun allergy is a rare type of hives and a mysterious disease that is not fully understood.
- It is important to know that there are no guidelines for the treatment of solar urticaria.
- Necessary precautions should be taken to avoid sun rays.
- High-dose antihistamines can be used for treatment.
- You can use lotions to relieve burning and redness on the skin.
- Those who fail conventional therapy can be treated with phototherapy, photochemotherapy, and biologic agents.
- In general, the prognosis for patients with severe urticaria is poor; many patients are confined indoors, leading to a poor quality of life.
- Solar urticaria usually lasts for a long time.