Solar urticaria, often known as sun allergy, is an uncommon allergy to sunlight that produces hives on sun-exposed skin.
Itchy, crimson patches or welts commonly emerge within minutes of being exposed to the sun. They might persist for a few minutes or several hours. The exact etiology of solar urticaria is unknown. Although the allergy might become chronic, the symptoms can be managed.
WHAT ARE THE SYMPTOMS OF SOLAR URTICARIA?
Sun allergy is characterized by reddish areas of skin that itch, sting, and burn.
The rash is more likely to afflict sections of your skin that aren't often exposed to sunlight. The rash may not appear on your hands or face, which are regularly exposed to sunshine. If you are extremely sun sensitive, hives may appear on portions of your skin that are covered by thin clothes.
The rash's appearance might vary based on individual sensitivity. The hives may blister or become crusty at times. When the rash heals, it leaves no scars.
If the hives cover a large portion of your skin, you may have additional allergic symptoms such as:
- Low blood pressure
- Wheezing
- Breathing difficulties
- Headache
- Nausea
- Fainting
These kind of allergy symptoms are more likely to occur if you spend a long period in the sun and expose big sections of your skin to the sun.
Solar urticaria can potentially induce anaphylaxis, however this is uncommon. Anaphylaxis is a potentially fatal disorder that need immediate medical attention.
WHAT ARE THE CAUSES OF SOLAR URTICARIA?
It is uncertain what causes solar urticaria. It happens when sunshine causes histamine or a similar substance to be released in your skin cells. An antigen-antibody response is used to explain the mechanism.
When your immune system generates antibodies to combat the specific antigen or irritant that reacts to sunlight, this sort of response happens. The resultant inflammatory response is hives.
You are more likely to get solar urticaria if you:
- Suffer from dermatitis
- Have a history of the condition in your family
- Use fragrances, disinfectants, dyes, or other chemicals that may cause the condition when exposed to sunlight on a frequent basis.
- Take antibiotics or other medications that may cause the disease, such as sulfa drugs
Certain wavelengths of ultraviolet (UV) light can cause an allergic response in certain people. The majority of persons who have solar urticaria react to UVA or visible light.
WHAT IS THE DIFFERENCE BETWEEN SUN ALLERGY AND HEAT RASH?
Heat rash develops when your pores get blocked and perspiration gathers beneath your garments or beneath your blankets. It can happen even if you are not exposed to sunshine.
In hot, humid conditions, for example, heat rash can appear on any region of your body that sweats, particularly in the folds of your skin. Heat rash is more likely in the following areas:
- Underneath your breasts
- In the groin
- Under your armpits
- Between the insides of your thighs
Solar urticaria, on the other hand, develops solely when exposed to sunshine.
Heat rash can develop at any time of year. When babies are enveloped in blankets, they might get heat rash. Heat rash normally fades away on its own after a few days, whereas solar urticaria usually only lasts a few hours.
How prevalent is sun allergy?
Solar urticaria is an uncommon allergy that affects people all over the world. The typical age of a person at the time of their first outbreak is 35, however it may afflict you at any age. It can even harm infants. Sun allergy can affect people of all ethnicities, while some types of the disorder may be more prevalent in white people.
HOW IS SOLAR URTICARIA DIAGNOSED?
A physical examination by your doctor may be able to detect solar urticaria. They will examine your rash and question you about its appearance and absence. Solar urticaria normally appears within minutes of sun exposure and subsides quickly if you go out of the sun. It leaves no visible scars.
Your doctor will inquire about your medical history as well as your sensitivity to sunshine. Your doctor may also order one or more of the following tests to confirm a diagnosis:
- Phototesting examines how your skin responds to UV radiation from a sun lamp at various wavelengths. The wavelength to which your skin reacts may aid in determining your specific sun allergy.
- Patch testing is applying several allergens to your skin, waiting a day, and then exposing your skin to UV light from a sun lamp. If your skin responds to a certain chemical, this might be what caused the solar urticaria.
- If your doctor suspects that your hives are caused by another medical illness, such as lupus or a metabolic disorder, blood tests or skin biopsies may be performed.
WHAT ARE THE TREATMENTS FOR SOLAR URTICARIA?
Solar urticaria can sometimes go away on its own.
The severity of your symptoms determines how you should be treated for solar urticaria. If your response is minor, staying out of the sun may alleviate your symptoms.
In moderate situations, your doctor may give antihistamines orally to alleviate the hives.
If your response is severe, your doctor may advise you to take additional drugs, such as corticosteroids. Some kinds of urticaria are treated with the antimalarial medication hydroxychloroquine (Plaquenil).
Phototherapy may also be recommended by your doctor. This therapy seeks to prepare your skin for the sun by exposing it to UV light from a sunlamp on a regular basis. This may desensitize you, but the effects may be short-lived.
Other therapies suggested by the British Association of Dermatologists include:
- Cyclosporine (Sandimmune), an immunosuppressant
- Omalizumab (Xolair)
- Plasma exchange
- Photopheresis
- Intravenous immunoglobulin
CONCLUSION
Solar urticaria may flare up just sometimes or it may be persistent. There have been few large-scale studies on treatment results, although a combination of treatments appears to be the most successful in addressing the illness.
A 2003 research of 87 patients discovered that keeping out of the sun, wearing dark clothes, and taking antihistamines helped roughly two-thirds of subjects. According to the same study, 36% of participants still benefitted from these approaches 15 years after diagnosis.
The majority of people who still experienced symptoms, according to the researchers, were able to achieve satisfactory symptom management using a mix of therapies.