A new study supported by our BRC is seeking to understand the causes of solar urticaria, and potentially find new ways to treat this rare and poorly understood disease.

Solar urticaria, also known as sun allergy, is a rare condition where sensitivity to sunlight causes itchy, red spots (‘hives’) to form on skin that is exposed to the sun. The hives usually appear within minutes of sun exposure. In severe cases, solar urticaria patients can even develop a life-threatening allergic reaction (anaphylaxis). The condition has a severe impact on people’s lives, as they have to stay inside to avoid sunlight and may become isolated.

This study will seek to understand the genetics underlying solar urticaria, by taking saliva samples from patients for genetic analysis. As part of the study, the researchers will also take skin samples from patients. They will look at the genes activated in the samples before and after they are exposed to light, in order to understand changes that are taking place in the skin.

Dr Sheila McSweeney is the researcher leading the study. She has been supported by our BRC to undertake a Clinical Training Fellowship to establish it.

She said: “Solar urticaria is currently a very poorly understood disease. Because it’s so rare, research is difficult, as you need to involve many patients to ensure the study is high-quality. We will be recruiting patients through our specialist photodermatology clinic and through other centres in the UK and across the world. We hope this will mean enough patients participate in our study to allow us to understand the causes of the disease.”

“At the moment, there are few effective treatments for this disease – patients have to resort to using thick sunscreen and clothing to shield from the sun, and have to organise their lives to spend as little time outside as possible. We hope that by understanding exactly what causes the disease, we could develop treatments that help solar urticaria patients to withstand sunlight, and do more of the activities that many of us take for granted.”

The Solar Urticaria Patient and Public Involvement Group advised Dr McSweeney on the development of the study. One of the patients who has been involved said:

“Eight years ago (aged 44), I walked past a window on a cloudy day and found out I had inexplicably become allergic to light – sunlight, strip light, low wattage bulb light – any light.

“From that very moment I could forget so many things I took for granted, and from then on was doomed to be in poorly lit rooms with the curtains drawn. My kids told their friend I was a ‘vampire’, as I would be the only dad darting between the shadows, wearing hoodies, hats and gloves on the hottest days!

“It has impacted my career, my life and those around me. I live with the hope someone can unravel and cure my immune system and improve the lives of all my fellow sufferers.”