Characteristics and Prognosis of Idiopathic Solar Urticaria

Abstract

Background: As little has been published on the course of idiopathic solar urticaria (SU) patients cannot receive comprehensive prognostic advice. Objective: To determine the prognosis and photobiological characteristics of idiopathic SU. Design: Historical cohort study, with inception cohort followed up from time of diagnosis. Follow-up for a median of 4 years (range, 3 months to 26 years) after diagnosis. Setting: Tertiary referral center for the investigation of photodermatoses in Scotland. Patients: The study included 87 patients, 61 (70%) of whom were female, with phototest-confirmed idiopathic SU between 1975 and 2000. Sixty patients (69%) were followed up clinically, and 25 patients (29%) were phototested on 2 or more occasions. Interventions: Investigations at time of diagnosis included monochromator phototesting. Further monochromator phototesting was performed in those patients in whom it was clinically indicated (select subgroup), and all patients who could be traced received a follow-up questionnaire. Main Outcome Measures: Characteristics of SU, responsible wave bands, and prognosis for clinical resolution. Results: The prevalence of idiopathic SU in Tayside, Scotland, is estimated to be 3.1 per 100000. Action spectra were typically broad, with 63% reacting to more than 1 wave band, and the most common provoking wavelengths were the longer UV-A and the shorter visible ones. The majority of subjects were affected perennially (68%), by radiation transmitted through glass (83%) and thin clothing (76%). Coexistent polymorphic light eruption occurred in 20 patients (23%), and another photodermatosis occurred in 6 patients, 3 of whom had chronic actinic dermatitis. In those with SU alone, the mean age at onset was 41 years. The probability of clinical resolution at 5 and 10 years after diagnosis was 0.12 (95% confidence interval, 0.06-0.24) and 0.26 (95% confidence interval, 0.15-0.43), respectively. Conclusion: Idiopathic SU is a chronic disease. The majority of this cohort was still affected after 5 and 10 years.

A Review of Solid State White Light Emitting Diode and Its Potentials for Replacing Conventional Lighting Technologies in Developing Countries

“…On the other hand, fluorescent lamps are associated with certain health effect as headache and fatigue caused by harmonics generated by the lamp and induces disease activity among individuals with pathological sensitivity to ultraviolet light. In rare cases some persons can get rash from fluorescent lamps (Colman et al, 1976;Binnie, 1979;Rihner & McGrath, 1992;Küller & Laike, 1998;Beattie et al, 2003). It is also thought that patients with conditions such as xeroderma, pigmentosun, lupus migraine, epilepsy, myalgic and autism could be aggravated by flicker and /or UV/blue light (especially UVB and UVC) (Millard & Hawk, 2001;SCENIHR, 2008).…”

Synergistic Effect of Broad-Spectrum Sunscreens and Antihistamines in the Control of Idiopathic Solar Urticaria

“…Most patients react to more than one wavelength group, with a greater proportion sensitive to UV-A and short visible wavelengths. 1 The clinical picture involves erythema and wheal formation with itch, most commonly after minutes of exposure to the pathogenic wavelengths, followed by fading of the reaction within a few hours. The severity of the symptoms varies tremendously, however, between patients and within each patient at various time points.…”

“…2 The course of idiopathic solar urticaria is usually long-term. In a comprehensive historical cohort study, 1 it was shown that clinical resolution occurred in 12%, 26%, and 36% of patients 5, 10, and 15 years after diagnosis, respectively, with another third showing clinical improvement with time. Approximately onequarter of the patients had the coexistence of other photodermatoses, primarily polymorphic light eruption, worsening the prognosis of the disease.…”

“…Approximately onequarter of the patients had the coexistence of other photodermatoses, primarily polymorphic light eruption, worsening the prognosis of the disease. 1 The exact mechanism behind the disease remains unknown but it has been hypothesized to rely on a photoallergen produced from a skin chromophore after absorption of the causal wavelengths. This photoallergen is subsequently recognized by specific IgE that binds to mast cells, causing degranulation of histamine and other mediators.…”

“…It has been described that only approximately one-third of patients benefit from using a sunscreen, whereas two-thirds may suppress their symptoms by using antihistamines. 1,7 However, to our knowledge, no standardized methods have been developed for the phototest procedure to determine the beneficial effect of combined sunscreen and antihistamine use. In the present study, we address this issue.…”