UK Study Maps Solar Urticaria Features and Treatments

TOPLINE:

In a multicentre cross-sectional study, the majority of patients with solar urticaria were of European ethnicity, with Fitzpatrick skin phototypes I-III; urticaria provocation was achieved using monochromator phototesting in 94.2% of participants, and omalizumab showed the highest complete response rate at 37.5%.

METHODOLOGY:

• Researchers conducted a cross-sectional study at six tertiary photobiology units in the United Kingdom between October 2019 and June 2023 and analysed clinical and photobiological features of 178 phototest-positive patients with solar urticaria.
• Included participants had a diagnosis of solar urticaria done by a consultant photodermatologist and successful urticaria provocation via phototesting.

TAKEAWAY:

• Overall, 67% of participants were women, with a median age of 35 years at disease onset, and the majority self-reported European ethnicity (89.2%), with Fitzpatrick skin phototypes I (16.6%), II (57.3%), and III (14.6%) being most prevalent (88.5%).
• Urticaria provocation was achieved using monochromator phototesting in 94.2% of participants and using solar simulated radiation in 5.8% of participants.
• Ultraviolet A (UVA) alone triggered symptoms in 31.3% of patients, UVA combined with visible light affected 29.4% of patients, and UVA with ultraviolet B affected 15.6% of patients.
• A treatment response analysis revealed that sunscreen and H1-antihistamines were most commonly used (98.2% and 97.6%, respectively), with partial response rates of 61.8% and 69.6%, respectively.
• Omalizumab demonstrated superior efficacy, with a partial response rate of 53.1% and complete disease control in 37.5% of patients compared with lower complete disease control for other treatments including montelukast (8.5%) and H1-antihistamines (13.5%).

IN PRACTICE:

“This study describes the clinical presentation of SU [solar urticaria] in 178 individuals and recapitulates several of its characteristics as reported by other investigators. Importantly, it highlights that SU affects individuals of all ethnicities and skin phototypes, although whether ethnicity-specific disease susceptibility exists cannot be ascertained from these data,” the authors wrote.

SOURCE:

This study was led by Navandeep K. Thumber, St John’s Institute of Dermatology, London, England. It was published online on April 28, 2025, in the British Journal of Dermatology.

LIMITATIONS:

This study was limited by the eligibility criteria excluding phototest-negative individuals and the subjective nature of treatment response reporting.

DISCLOSURES:

This research did not receive any specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The authors reported having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.