| • | pruritic wheals arising after 5 to 10 minutes of sun exposure, but resolve within a few hours |
| • | an immediate type 1 hypersensitivity response to a cutaneous or circulating photo-allergen generated from a precursor after the absorption of light energy |
| • | action spectrum = 300nm to 500nm (i.e. includes visible light) |
| • | treatment: UVB or PUVA to “harden” |
| • | treatment: non-sedating H1 antihistamines significantly increase the minimal whealing dose |
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