Action Spectra in Idiopathic Solar Urticaria..

A complex photodermatosis: solar urticaria progressing to polymorphic light eruption

“…Such a clinical picture is highly unusual in our experience, although a delayed papular response following solar urticaria was thought by Magnus et al to be quite common. 11 It is not entirely clear whether this latter phenomenon is PLE as we now describe since the previous reports were not supported by histopathology. Nonetheless, the localization of PLE to sites of solar urticaria in rare patients suggests there may very possibly be a common inducing photoallergen involved in such cases.…”

Changes of photosensitivity and action spectrum with time in solar urticaria

“…In this series, of the seven individuals who demonstrated abnormal phototest results, only one developed reactions to a single wavelength, while others either reacted to a broad range from UVB through to visible light, or from UVA to visible light. This broad range of action spectrum has also been observed previously, with 10 of the 17 subjects in one study having an action spectrum throughout the UV range, with or without involvement of the visible light range (8).…”

“…However, there is considerable variation in the action spectrum reported in the literature. Visible light (2–7), ultraviolet (UV) B (4–6, 8, 9), and UVA (4–6, 9–12) have all been shown to be implicated, and the action spectrum may vary widely between individuals. Furthermore, phototesting using more than one light source may be required to produce the triggering wavelengths.…”

New Subtype of Solar Urticaria?

“…action spectrum and serum fac tor, Harber et al [1] distinguished six types of SU. Later Ive et al [3] on the basis of action spectra alone mentioned types A-D. In the meantime Horio [4] was able to show that the photosensitizer might be a serum factor whose molecular weight is more than 10s daltons.…”