The inhibition spectrum of solar urticaria suppresses the wheal-flare response following intradermal injection with photo-activated autologous serum but not with compound 48/80

Solar urticaria: clinical characteristics, treatment effectiveness, long-term prognosis, and QOL status in 29 patients

Introduction

Solar urticaria (SU), a relatively rare skin inflammatory and photosensitivity disease, is often resistant to standard urticaria treatment. Quality of life (QOL) among SU patients has not been extensively explored. This study was performed to clarify the clinical features and effectiveness of therapies (e.g., hardening therapy) for SU and to determine QOL among SU patients.

Methods

The authors examined the characteristics, treatments, and QOL statuses of 29 Japanese SU patients using medical records and a questionnaire approach.

Results

Among 29 patients, H1 antihistamine therapy (H1) was effective in 22 (75.8%) patients. H2 antihistamine therapy (H2) was effective in three of seven (42.9%) patients. Ultraviolet radiation A (UVA) hardening therapy was effective in eight of nine (88.9%) patients. Visible light (VL) hardening therapy was ineffective in three of three patients. In one patient who underwent both UVA and VL hardening therapy, only UVA hardening therapy was effective. In the questionnaire, 18 patients (90%) reported some improvement compared with disease onset (four had complete remission, six had completed treatment although mild symptoms persisted, and eight were receiving treatment with moderate symptoms), whereas two patients reported exacerbation. Patients in complete remission had a mean disease duration of 4 years, whereas patients not in remission had a mean disease duration of 8.8 years. The mean Dermatology Life Quality Index (DLQI) score for the current status was 7.4. There was a correlation between DLQI and symptom/treatment status. However, neither DLQI and action spectra nor DLQI and treatments exhibited significant differences.

Discussion

The questionnaire revealed current QOL status and long-term prognosis in SU patients. Compared with disease onset, most patients showed improvement when assessed for this study. Both H1 and H2 should be attempted for all SU patients. UVA hardening therapy may be an option for SU patients with an action spectrum that includes UVA.

Characteristics and clinical significance of augmentation spectra in solar urticaria

Solar urticaria has unique spectra, such as inhibition and augmentation. The clinical significance of these spectra, especially augmentation, is not well understood. Reported cases of solar urticaria with augmentation spectra are extremely rare in the published English-language work. The purposes of this study were to evaluate the clinical features of solar urticaria with augmentation spectra and to elucidate the mechanisms and clinical importance of the spectra. We experienced 11 cases (five females, six males; mean age, 40.1 years; range, 1-74) of solar urticaria with augmentation spectra from April 2007 to July 2019. Augmentation spectra were UV-B in three cases, UV-A in two, visible light in four, UV-A and UV-B in one, and UV-A and visible light in one. Augmentation spectra were observed before action spectra in four cases, after in six, and before and after in one. Injection of sera irradiated with action spectra and augmentation spectra in vitro induced stronger immediate reactions than those of only action spectrum-irradiated sera in four of five cases. The results of injection tests suggested that augmentation spectra enhance the production of urticaria-forming factor. Clinically, we observed severe urticarial reactions in four cases, including anaphylaxis in three and moderate urticarial reactions in three. These results suggest that augmentation spectra are not as rare as previously thought and that they are associated with the severity of solar urticaria. Therefore, phototesting for both augmentation and action spectra should be performed to provide appropriate guidance for patients with solar urticaria.

Ultraviolet radiation and skin mast cells: Effects, mechanisms and relevance for skin diseases

Mast cells (MCs) are well known as versatile effector cells in allergic reactions and several other immune responses. Skin MCs and cutaneous MC responses are subject to the effects of environmental factors including ultraviolet radiation (UVR). Numerous studies have assessed the effects of UVR on MCs, in vitro and in vivo. Interestingly, UVR seems to have variable effects on non-activated and activated mast cells. In general, UV therapy is beneficial in the treatment of urticaria and mastocytosis, but the effects are variable depending on treatment regimen and type of UVR. Here, we review and summarise key reports from the older and current literature on the crosstalk of UVR and skin MCs. Specifically, we present the literature and discuss published reports on the effects of UVR on skin MCs in rodents and humans. In addition, we review the role of MCs in UVR-driven skin diseases and the influence of UV light on MC-mediated skin diseases. This summary of our current understanding of the interplay of skin MCs and UVR may help to improve the management of patients with urticaria and other MC disorders, to identify current gaps of knowledge, and to guide further research.

Influence of narrowband UVB irradiation of serum on autologous serum skin test results

BACKGROUND

Autologous serum skin test (ASST) is an in vivo test to demonstrate circulating endogenous proinflammatory or wheal-inducing factors in urticaria patients. While ASST was negative in a patient with solar urticaria and in a patient with localized heat urticaria, test results turned to positive when performed with visible light-irradiated and heated serums, respectively. These data suggest that some factors and/or antibodies in serum may be activated or inhibited with different factors. We aimed to investigate whether or not ASST results change when performed with narrowband ultraviolet B (UVB)-irradiated serum.

MATERIALS AND METHODS

Seventy-seven patients with chronic idiopathic urticaria underwent ASST twice in consecutive days. The second ASST was performed with narrowband UVB-irradiated serum. The results of the first and second ASSTs were compared.

RESULTS

The first ASST results were positive in 46 (59.7%) patients. ASST results reversed oppositely in 36 (46.8%) patients, turned from negative to positive in 19 patients, and turned from positive to negative in 17 patients when performed with narrowband UVB-irradiated serum.

CONCLUSION

 Our results suggest that narrowband UVB may have modifying effects on some wheal-inducing factors and/or antibodies. On which factors in serum narrowband UVB has effects may be investigated.

Immunologically mediated photodermatoses: diagnosis and treatment

Electromagnetic radiation may cause distinct skin conditions. The immunologically mediated photodermatoses (IMP, previous term: idiopathic photodermatoses) represent a heterogenous group of disorders presenting with pathologic skin reactions caused by optical radiation, particularly in the UVA wavelength region. The exact pathomechanism in IMP remains to be elucidated; however, it is very likely (auto)-immunologic in nature. Polymorphic light eruption, actinic prurigo, hydroa vacciniforme, chronic actinic dermatitis, and solar urticaria are the most important conditions that may be summarized under the term IMP. IMP frequently result in a significant reduction in quality of life in affected individuals, mainly because of troublesome symptoms such as intractable itch and pain. Photodiagnostic procedures are mandatory for the exact determination of action spectra and the degree of photosensitivity. Broad-spectrum photoprotection is essential in the prevention of IMP. Photo(chemo)therapeutic regimens are predominantly used to increase the cutaneous immunologic tolerance against ambient UV radiation. In severe forms of IMP, immunomodulatory and immunosuppressive therapies may need to be considered. Overall, IMP form a significant group of skin conditions that can be extremely disabling to the patient and are difficult to diagnose and treat.