Sun Allergy Hives That Appear Within Minutes
Solar urticaria is a rare form of physical hives triggered by ultraviolet or visible light. Welts appear on sun-exposed skin within minutes and typically fade within an hour or two after you leave the light. It can begin at any age, most often in young adults.
Symptoms
Itching or burning is followed by red wheals on exposed skin such as the arms, chest and neck. Skin covered by clothing is usually spared, at least at first. Large areas of exposure can cause headache, nausea, wheezing or faintness.
Solar Urticaria vs Other Sun Reactions
Polymorphic light eruption appears hours to days after sun, lasts longer and looks like small bumps or blisters. Solar urticaria begins within minutes and fades fast. Heat can also cause hives; compare with heat hives.
Diagnosis
Dermatologists use phototesting, exposing small skin areas to measured wavelengths of light, to confirm the diagnosis and identify which wavelengths trigger it.
Protecting Your Skin
- Use broad-spectrum sunscreen; tinted sunscreens block visible light.
- Wear tightly woven, long-sleeved clothing and wide-brimmed hats.
- Take non-sedating antihistamines as directed by your doctor.
- Ask about add-on options if antihistamines do not control symptoms.
Read about related types of hives.
When to Call 911
Go to the emergency room or call 911 immediately if hives are accompanied by difficulty breathing, wheezing, throat tightness, swelling of the lips, tongue or face, light-headedness or a sense that something is seriously wrong. These are warning signs of anaphylaxis.
When to See a Doctor
See a doctor if your symptoms last more than a few days, keep coming back, cover large areas, or interfere with sleep or daily life. Dr. Tiffany Young and the Hives Treatment Center in San Francisco provide online and in-person care for solar urticaria.
Related Reading
You may also find these guides helpful: causes of hives and hives symptoms.
Frequently Asked Questions About Solar Urticaria
Is solar urticaria rare?
Yes, it accounts for a small portion of urticaria cases.
Can I still go outside?
Many people can with protection and treatment. Gradual exposure may build tolerance in some.
Does window glass block the trigger?
Glass blocks UVB but not necessarily UVA or visible light, which can still trigger some people.
Get Relief for Your Hives
Sun-triggered hives are treatable with the right plan. Visit our hives treatment page to see the latest treatment options for your outbreak.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. If you think you are having a medical emergency, call 911.
