Efficacy of Therapies for Solar Urticaria: A Systematic Review and Meta-Analysis

Background: Solar urticaria is a rare and disabling photodermatosis. Due to its low prevalence, most available data regarding treatment are derived from observational studies and case series, and a systematic evaluation of treatment efficacy is lacking. This systematic review and meta-analysis aims to assess therapeutic outcomes across treatment modalities in order to guide clinical care. Methods: We conducted a systematic literature search across PubMed, ScienceDirect, the Cochrane Library, and ClinicalTrials.gov. Studies reporting treatment outcomes in patients with solar urticaria were included. Pooled response rates were calculated for each treatment modality. Results: Out of 508 studies initially identified, 38 met the inclusion criteria. Antihistamines were evaluated in 21 studies (376 patients), with a pooled response rate (partial or complete) of 83.0% (95% CI, 70.4-91.1%) and a complete response rate of 7.7% (95% CI, 1.7-28.3%). Phototherapy was assessed in 11 studies (145 patients), showing a similar overall response (89.8%; 95% CI, 77.9-95.3%) but a higher complete response rate (39.8%; 95% CI, 18.3-66.1%). Omalizumab, evaluated in nine studies (76 patients), demonstrated the highest efficacy, with 93.2% (95% CI, 73.8-98.5%) achieving response and 68.4% (95% CI, 48.5-83.2%) complete remission. Limited data on IVIG, cyclosporine, and plasmapheresis suggested partial efficacy in selected refractory cases. Conclusions: This meta-analysis may support clinical decision-making by clinicians. A stepwise approach is suggested: high-dose H1 antihistamines as first-line therapy, phototherapy as an alternative option in patients with access to treatment centers, and omalizumab for those with insufficient response. In refractory cases, additional options might be considered.