title: Analysis of solar urticaria in Thai patients.
abstract: BACKGROUND
  Solar urticaria (SU) is an uncommon photodermatosis characterized by erythema and whealing within minutes to a few hours after exposure to sunlight or an artificial light source.
  
  
  OBJECTIVE
  To determine the clinical features, photobiological characteristics and treatment outcomes in Thai SU patients visiting a tertiary referral hospital.
  
  
  METHODS
  A retrospective analysis of 13 patients with SU was conducted. Demographic data, disease characters, phototesting results, laboratory investigations, treatment and outcome were evaluated.
  
  
  RESULTS
  Of the 13 patients diagnosed with SU from 2000 to 2012, most patients were female (10, 77%). The mean age of onset was 29 years (15-51). The mean duration of SU was 46 months (6-120) at presentation. The most common affected location was the upper extremities (92%), followed by head and neck (77%). The responsible action spectra were visible light in 8 patients (61.5%), ultraviolet A (UVA) in 1 patient (8%), and both visible light and UVA in 4 patients (31%). The median course from disease onset to disease resolution was 63 months (95% confidence interval 30-95). After 13 months and 55 months from the onset of symptoms, 23% and 49% of patients, respectively, were predicted to recover from their symptoms.
  
  
  CONCLUSIONS
  Solar urticaria is a rare condition in Thailand. The common eliciting spectra of SU were visible light and UVA. Management of SU remains challenging.
authors.affiliation: Department of Dermatology Faculty of Medicine Siriraj Hospital, Mahidol University 2 Wanglang Road, Bangkoknoi, Bangkok, THAILAND 10700.
authors.forename: Narumol
authors.initials: N
authors.lastname: Silpa-Archa
authors.forename: Chanisada
authors.initials: C
authors.lastname: Wongpraparut
authors.forename: Vichit
authors.initials: V
authors.lastname: Leenutaphong
mesh_terms: D000293:Adolescent; D000328:Adult; D017454:Dermatitis, Photoallergic / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D012189:Retrospective Studies; D012307:Risk Factors; D012867:Skin / Q000473:pathology / Q000528:radiation effects*; D013472:Sunlight / Q000009:adverse effects*; D062606:Tertiary Care Centers; D013785:Thailand; D013997:Time Factors; D016896:Treatment Outcome; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014581:Urticaria / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D055815:Young Adult