What are the other Names for this Condition? (Also known as/Synonyms)

• SU (Solar Urticaria)
• Sunlight-Induced Angioedema-Urticaria

What is Solar Urticaria? (Definition/Background Information)

• Solar Urticaria (SU) is a rare skin condition in which individuals develop urticaria (reddish welts on the skin) or hives after exposure to ultraviolet rays. The hives may develop on non-exposed areas of the body too
• The cause of the condition is unknown, but it is believed to be a type of hypersensitivity reaction. A family history of Solar Urticaria is identified as a risk factor for the condition
• Some individuals have a higher sensitivity to UV light than others and are hence more prone to the condition. The affected body regions typically display rashes with itching sensation. Sometimes, nausea, vomiting, and body aches may be observed
• Solar Urticaria is treated using antihistamines, desensitization phototherapy, and immunosuppressive medication in case of severe signs and symptoms. The prognosis with adequate treatment is usually excellent
• Solar Urticaria may be prevented by avoiding direct sun-exposure, the use of sun screen lotions and protective clothing

Who gets Solar Urticaria? (Age and Sex Distribution)

• Solar Urticaria is a rare condition that may be observed in all those who are exposed to ultraviolet light (either from the sun or from other sources). There is no age, gender, race, or ethnic preference observed
• However, light-skinned individuals (such as Caucasians) are more prone to the condition than dark-skinned individuals (such as Africans or Asians)
• Generally, individuals in latitudes around tropical areas and individuals living in higher altitudes have a higher risk

What are the Risk Factors for Solar Urticaria? (Predisposing Factors)

The risk factors for Solar Urticaria include:

• Exposure to intense sun for long periods during the course of work, or due to participation in outdoor sports or other such activities
• Those who work outdoors when sun intensity is at its highest; the sun is a big source of ultraviolet light and highest exposure is around noon
• People living in tropical or subtropical geographical regions
• The presence of snow or ice may increase the reflective component of sun’s UV light
• A positive family history of Solar Urticaria
• Fairer-skinned individuals have a greater risk of Solar Urticaria than darker-toned individuals

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Solar Urticaria? (Etiology)

• The cause of development of Solar Urticaria is unknown. It is termed as a type 1 hypersensitivity reaction
• The skin rashes are seen to form on exposure to ultraviolet radiation, which may be from sources such as the sun or tanning lamps

What are the Signs and Symptoms of Solar Urticaria?

The signs and symptoms of Solar Urticaria usually include:

• Formation of urticaria or hives; the skin rashes usually go away after a few hours
• Pain, pain on touch
• Itching of skin
• These signs and symptoms occur on skin areas that have been exposed to ultraviolet light, and on non-exposed skin areas too
• Typical body regions affected include: Face and lips, neck, arms, chest, and trunk
• Sometimes, body aches, nausea and vomiting may be observed
• Very rarely, asthma-like symptoms can occur

How is Solar Urticaria Diagnosed?

A diagnosis of Solar Urticaria may be made by the following tests and exams:

• Physical examination of the skin and medical history evaluation
• Photosensitivity patch test: In this test, abnormal skin reaction to exposed UV light is tested
• Photo provocation test
• Skin biopsy: A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Note: A skin biopsy is usually unnecessary and is performed only in rare cases.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible complications of Solar Urticaria?

The possible complications due to Solar Urticaria may include:

• Discomfort, irritability of the affected skin
• The affected areas can heal with either increased or decreased pigmentation
• Cosmetic concerns in some individuals leading to stress

How is Solar Urticaria Treated?

The treatment measures for Solar Urticaria include:

• Topical treatment that may include cooling the skin using moist towels and moisturizing creams to soothe the condition
• Oral anti-histamine therapy
• Desensitization phototherapy
• In individuals with severe signs and symptoms, immunosuppressive medication may be administered

How can Solar Urticaria be Prevented?

A few methods to prevent Solar Urticaria include:

• Avoiding prolonged and chronic exposure to the sun (to the extent possible)
• Taking safety steps to reduce exposure to the UV rays, by using sunscreens with high sun-protection factor, wide-brimmed hats, and protective clothing
• Being aware of the hazards of prolonged sun exposure and taking steps to protect oneself. Modifying one’s profession to stay out of the sun during the period, when it is at its most intense
• Avoiding excessive sunbathing (particularly if one is fair-skinned), use of tanning beds, sun lamps, and chemical agents, that accelerate sun tanning
• Individuals who are regularly exposed to the sun, or work under the sun should get their skin periodically examined by a physician. This is crucial if they suspect or notice any skin changes
• Keeping oneself well-hydrated if sun-exposure for prolonged periods is unavoidable

What is the Prognosis of Solar Urticaria? (Outcomes/Resolutions)

The prognosis of Solar Urticaria is generally excellent with appropriate treatment.

Additional and Relevant Useful Information for Solar Urticaria:

Sunburn is another skin condition that is caused by ultraviolet rays of the sun. It occurs when skin cells are burnt or damaged from exposure to the UV component of the sun

The following article link will help you understand sunburn:

https://www.dovemed.com/diseases-conditions/sunburn/