ACTION SPECTRA IN IDIOPATHIC SOLAR URTICARIA

Solar urticaria in 145 patients: Assessment of action spectra and impact on quality of life in adults and children

BACKGROUND

Solar urticaria (SU) is a rare chronic inducible urticaria triggered via uncharacterized chromophores. We detail responses of a large patient series to monochromator phototesting and broadband ultraviolet radiation (UVR); relationship to life quality is explored.

METHODS

Retrospective review of all SU patients undergoing standardized diagnostic photoinvestigation at a specialist centre during 2000-2016. From 2011, patients completed dermatology life quality index (DLQI) questionnaires for the past week and year.

RESULTS

In 145 patients (mean: 35.8, range: 3-69 years; 18 aged <18 years; 100 female), combined phototesting with broadband UVR and monochromator sources successfully provoked 74.5% patients, with 65.6% provoked by broadband UVR alone and 57.9% by monochromated radiation alone. The narrow wavebands most frequently eliciting wheal and flare response were between 370 and 400 nm, with 25% patients at 300 ± 5 nm, 53.6% at 320 ± 10 nm, 66.7% at 330 ± 10 nm, 77.4% at 350 ± 20 nm, 83.3% at 370 ± 20 nm, 86.9% at 400 ± 20 nm, 44% at 500 ± 20 nm and 17.8% at 600 ± 20 nm. In 62 patients, the DLQI revealed 56.1% had very to extremely large impact in the past week (all patients: mean score: 11.1, range: 0-29) rising to 69.8% for the past year (12.5, 0-30); adults and children were similarly affected. Patients with positive photoprovocation had higher DLQI score than those who were negative (DLQI for past week: mean: 12.6 ± SEM 1.1 vs 4.6 ± 1.4, P < .01).

CONCLUSION

SU is predominantly provoked by longer UVA-shorter visible radiation, which penetrates window-glass and where sunscreens are less effective; impact on life quality is considerable. Photoprotective agents effective against this spectrum are needed.

Changes of photosensitivity and action spectrum with time in solar urticaria

BACKGROUND

Solar urticaria is a rare photosensitivity disorder characterized by the rapid onset of a pruritic, erythematous and urticarial rash following sun-exposure. The action spectrum and degree of photosensitivity have been observed to change over time in several isolated reports.

METHODS

Monochromator phototesting was performed on multiple occasions on 12 patients with solar urticaria.

RESULTS

Six patients demonstrated normal responses in the initial phototest. They remained normal in five patients upon subsequent testing. Seven patients demonstrated abnormal immediate responses, most frequently at UVA wavelengths. Within some individuals, variations in action spectrum and/or degree of photosensitivity were observed over the years, but not over days.

CONCLUSION

Significant changes in action spectrum and degree of photosensitivity may occur over years in solar urticaria. However, changes over shorter periods of time are likely to be minor and not have clinical significance.

A complex photodermatosis: solar urticaria progressing to polymorphic light eruption

We report an unusual case of localized solar urticaria which progressed on each occasion to polymorphic light eruption (PLE); this was initially noted following provocation by narrow band ultraviolet B (311-313 nm) phototherapy.

Fixed solar urticaria

BACKGROUND

Three unusual cases of solar urticaria limited to fixed skin sites are described.

OBJECTIVE

Our objective was to study the clinical course and several therapeutic regimens for fixed solar urticaria.

METHODS

Phototesting and in vitro activation of a plasma factor were performed.

RESULTS

Wheals in a patchy pattern were strictly localized to the same circumscribed skin areas; they were reproducible in their pattern and location by irradiation. The action spectra ranged from 320 to 700 nm, 320 to 585 nm, and 400 to 560 nm. In one patient inhibition was found by wavelengths between 280 and 320 nm. Intradermal injection of the patients' plasma activated by in vitro irradiation induced wheals only in the affected skin sites. The patients showed a good therapeutic response to H1-antihistamines or repeated exposures to natural sunlight.

CONCLUSION

The term fixed solar urticaria is proposed for this peculiar type of solar urticaria.

Familial dermographism

Urticaria in response to various physical stimuli has been reported in sporadic and familial patterns. The most common of these physical urticarias, dermographism, is a localized urticarial response to stroking or scratching of the skin and has not been reported previously to be familial. A four-generation family with dermographism, probably inherited as an autosomal dominant trait, is presented along with a discussion of sporadic dermographism and other types of familial physical urticarias.

A case of actinic prurigo and solar urticaria

Actinic prurigo and solar urticaria are uncommon chronic idiopathic photodermatoses in the United Kingdom. To our knowledge, their occurrence in the same patient has not hitherto been described.

Pathogenesis and classification of solar urticaria: a new concept

Although its exact mechanism remains unknown, evidence supports the immunologic nature of solar urticaria. On the basis of experimental findings in the literature and our own observations, a new concept of the pathogenesis and classification of solar urticaria is presented. We propose two types of solar urticaria: type I, IgE-mediated hypersensitivity to specific photoallergens, which are generated only in patients with solar urticaria, and type II, induction of IgE-mediated hypersensitivity to a nonspecific photoallergen, which is generated both in patients with solar urticaria and in normal persons.

Indoor and outdoor efficacy testing of a broad-spectrum sunscreen against ultraviolet A radiation in psoralen-sensitized subjects

The efficacy of a sunscreen containing an investigational drug, butyl methoxydibenzoylmethane in combination with padimate O against the erythemogenic effect of ultraviolet A (UVA) radiation was evaluated in two double-blind studies involving subjects sensitized with topical 8-methoxypsoralen. UVA radiation was supplied from either a filtered solar simulator (indoors) or filtered sunlight (outdoors). Five formulations were tested: 3% butyl methoxydibenzoylmethane and 7% padimate O, 7% padimate O, 5% octyl salicylate, and 3% oxybenzone, 3% butyl methoxydibenzoylmethane alone, 7% padimate O alone, and vehicle. Sunscreen protection against the erythemogenic effect of UVA radiation was expressed as phototoxic protection factors. The phototoxic protection factor for each sunscreen was derived from a ratio of the minimal phototoxic dose of UVA radiation that produced delayed erythema on sunscreen-protected and unprotected skin. The combination of 3% butyl methoxydibenzoylmethane and 7% padimate O provided significantly greater protection than the other sunscreen formulations, and for each sunscreen the phototoxic protection factors determined indoors and outdoors were comparable.

The contributions of UVA and UVB to connective tissue damage in hairless mice

UVA, in high-dose single exposures, can, like UVB, be deleterious to skin. Dermal damage resulting from chronic exposure to UVA has not been studied. To investigate the long-term effects, we irradiated albino hairless mice for 30-34 weeks with UVA radiation, alone, from two sources with differing spectral qualities, and in combination with UVB as solar-simulating radiation. The results were compared to UVB alone. Like UVB, the UVA waveband, especially that with a spectral distribution similar to solar UVA, caused elastic fiber damage, increased glycosaminoglycan levels, and produced hypertrophy of deep dermal tissues. There were, however, striking differences between UVB- and UVA-irradiated skin. A combination of UVA and UVB summated the effects of both wavebands. Substantial protection against these effects was afforded by a broad-spectrum sunscreen.

Ultraviolet A phototherapy in the prophylaxis of solar urticaria

Five patients with solar urticaria were treated with ultraviolet A (UVA) radiation. Three experienced marked increases in sunlight tolerance, but two patients failed to improve. Subjective clinical improvement was documented objectively by marked increases in the minimal urtication doses obtained by provocative light testing. These results indicate that some patients with solar urticaria may respond to treatment with UVA radiation alone.

Topical protection against long-wave ultraviolet A

A PABA ester-oxybenzone preparation is superior to PABA or sulisobenzone alone in protecting the skin from methoxsalen-induced ultraviolet A (UVA) phototoxicity after water substantivity challenge. Such a mixture would be useful as a UVA screen for uninvolved or actinically damaged skin in patients receiving psoralens and ultraviolet A (PUVA) therapy. An effective topical UVA screen also may protect against UVA-induced diseases like solar urticaria, polymorphic light eruptions, drug-induced phototoxicity or photoallergy, and possibly against the deep degenerative changes of solar elastosis.

Histologic changes associated with ultraviolet A--induced erythema in normal human skin

We have examined the effects of a standardized, moderately erythemogenic dose of long-wave ultraviolet (UVA) radiation on normal human skin, with the use of an appropriately filtered solar simulator and sequential biopsy specimens processed as 1-micron Epon-embedded sections. Histologic changes were present immediately after irradiation and evolved slowly during the 48-hour study. The epidermis manifested slight intracellular and intercellular edema and progressive loss of Langerhans cells to approximately one-fifth control values. A dermal infiltrate of neutrophilic polymorphonuclear leukocytes was present in all postirradiation specimens and peaked at 3 hours. A perivascular lymphocytic infiltrate, moderate endothelial cell enlargement, mast cell hypogranulation, occasional massive venular dilation, and sparse red blood cell extravasation were also noted. Overall, our findings expand and quantify earlier impressions that, compared to UVB, UVA has a relatively greater histologic effect on the dermis than on the epidermis, depletes epidermal Langerhans cells, and recruits neutrophils into irradiated human skin.

Treatment of urticaria

Urticaria represents a wide variety of conditions characterized by urticarial papules, wheals, and angioedema. The number of potential causes of urticaria is legion, but a diligent search by careful history and examination is indicated. Laboratory testing depends upon the specific situation, but routine screening examinations are not cost effective. Histamine from mast cells plays an important role in urticaria. Multiple factors, such as aspirin and other nonsteroidal anti-inflammatory agents, direct histamine-releasing agents (including benzoates), tartrazine and other azo dyes, and perhaps blockers of beta 2-adrenergic activity and H2 receptors, adversely influence histamine release either directly or indirectly. Vasodilation is also detrimental. Treatment of both acute and chronic urticaria necessitates removal of the patient from aggravating factors as well as the cause of the outbreak (if one can be found), along with effective antihistaminic agents and perhaps beta 2-adrenergic agonists. Treatment of specific entities within the urticarial group is briefly outlined in this article.

Solar urticaria: treatment with PUVA and mediator inhibitors

Several therapeutic regimes for solar urticaria were evaluated. A short course of PUVA therapy produced a marked increase in the minimal dose of radiation required to produce urticaria in the six patients treated. This objective evidence of improvement was supported by the patients' reports of greatly increased tolerance to sun-exposure. Chlorpheniramine, an antihistamine, produced a slight increase in the minimal dose of radiation necessary to produce urticaria but its effectiveness was limited by side-effects. Indomethacin, an inhibitor of prostaglandin synthetase, produced no beneficial effect.

Effect of H1-and H2-receptor antagonists on cutaneous inflammation evoked by histamine analogues and UV radiation

The effect of mepyramine, cimetidine and a combination of both types of histamine receptor antagonist on the cutaneous vasodilatation, increased vascular permeability and oedema formation associated with UV injury was quantitatively evaluated. The specificity of the histamine antagonists employed in this study was verified by examining their effect on the vascular changes produced by selective H1- and H2-receptor agonists. The immediate, transient increase in vascular permeability and hyperaemia evoked by UV radiation was substantially reduced by a combination of mepyramine and cimetidine whereas the vascular changes which comprise the delayed, prolonged phase of the inflammatory response remained unaltered by histamine receptor blockade. It is concluded that histamine plays a major role in mediating the initial, transient phase of UV-induced inflammation but does not appear to be involved in mediating the subsequent sustained vascular changes.

Instrumentation and action spectra in light-associated diseases

Instrumentation for studying action spectra in controls and various light-associated diseases is described. This study summarizes tests performed with a prism grating monochromator during the last 10 yr. There were 68 photodermatoses studied: xeroderma pigmentosum (XP) (1), lupus erythematosus (LE) (12), polymorphous light eruption (PLE) (23), solar urticaria (4), actinic reticuloid (2), halogenated salicylanilide photosensitivity and persistent light reactors (11), psoralen photosensitivity (6), and porphyria (9). A normal minimal erythema dose in the UVB (below 320 nm) was generally observed in polymorphous light eruption and lupus erythematosus. The most exquisite photosensitivity for delayed erythema was observed in actinic reticuloid, which in one case was 25-35 times more sensitive in the UVB range which was also observed but to a lesser extent in XP and in persistent light reactors. Persistence of erythema and edema at test sites was observed in XP, PLE, LE, and actinic reticuloid. A delay in development of erythema reaching a maximum at 72 hr was observed in XP and psoralen phototoxicity. Maximum photosensitivity occurred in solar urticaria. Three patients had peak sensitivity in the range of 310-313 nm and the 4th at 460 nm. Photosensitivity in the visible range was detected in 2 patients with solar urticaria, one with actinic reticuloid, and confirmed in 9 patients with porphyria (405 nm). Photosensitivity in the UVA (above 320 nm) occurred to some degree in all groups.

Dermo-distortive urticaria: an autosomal dominant dermatologic disorder

A new hereditary physical urticaria, dermo-distortive urticaria (DDU), is described in a Christian Lebanese family. DDU is characterized by the appearance of pruritic, erythematosus, edematous, cutaneous swelling confined to the stimulated area in response to stimuli that vibrate or stretch the skin in a repetitive manner. The lesions appear within several minutes after stimulation and disappear within an hour. Extensive stimulation causes not only local urticaria but also a systemic response of faintness, headache, and facial erythema. Other than these annoying reactions, no other morbidity is associated with this disorder. While this disorder is certainly uncommon and its manifestations are more annoying than life threatening, it may be an important example of a heritable defect of inflammation control mechanisms. Although the mediator for the urticaria and systemic response was not isolated, a likely candidate is histamine. Computer analysis of the phenotype of 219 relatives in 6 generations shows that DDU is transmitted as an autosomal dominant trait with high penetrance. DDU is clinically distinct from hereditary angioneurotic edema, pressure urticaria, and dermographia. It is similar to vibratory angioedema (VA), but sufficient evidence to prove that DDU and VA are identical is not available.

Elevated blood histamine levels and mast cell degranulation in solar urticaria

1 Ultraviolet radiation (UVR)-induced wealing was studied in four patients with solar urticaria, whose measured action spectra were within the range 300 to 700 nm. 2 Elevated histamine levels were found in blood draining wealed skin in all four patients. 3 Histological and electron microscopial studies of the irradiated skin showed evidence of mast cell degranulation. 4 These findings demonstrate an association between histamine release from mast cells and wealing in solar urticaria, and should encourage evaluation of drugs which suppress histamine release in this disorder.

A new dosemeter for the measurement of natural ultraviolet radiation in the study of photodermatoses and drug photosensitivity

The production and optical properties of a dosemeter for natural ultraviolet radiation are descirbed. The physical form of the dosemeter is a thin polymer film which incorporates 8-methoxypsoralen as the chromophore. The dosemeter responds to ultraviolet radiation at wavelengths up to 380 nm and is suitable for quantifying the UV exposure of patients suffering from some idiopathic photodermatoses or drug photosensitivity.