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For further information, see CMDT Part 6-52: Photodermatitis
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Essentials of Diagnosis
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Painful or pruritic erythema, edema, or vesiculation on sun-exposed surfaces: the face, neck, hands, and "V" of the chest
Inner upper eyelids spared, as is the area under the chin
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General Considerations
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Composed of four groups:
Primary, idiopathic immunologically mediated photodermatoses
Drug- or chemical-induced photodermatoses
Dermatoses that are worsened or aggravated by UV exposure
Genetic diseases with mutations predisposing to photodermatitis
Primary photodermatoses include polymorphic light eruption, chronic actinic dermatitis, and actinic prurigo
Drug- or chemical-induced photodermatitis may be either exogenous (manifests as phototoxicity or photoallergy) or endogenous (eg, porphyria cutanea tarda, pellagra) in origin
Contact photosensitivity may occur with plants, perfumes, and sunscreens
Dermatoses that are worsened or aggravated by UV exposure include systemic lupus erythematosus and dermatomyositis
Three percent of persons with atopic dermatitis, especially middle-aged women, are photosensitive
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Acute inflammatory phase of phototoxicity, which, if severe enough, is accompanied by
Erythema, edema, and possibly vesiculation and oozing on exposed surfaces
Peeling of the epidermis and pigmentary changes often result
The lower lip may be affected
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Differential Diagnosis
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When the eruption is vesicular or weepy, treatment is similar to that of any acute dermatitis, using cooling and soothing wet dressing
Mid-potency to high-potency topical corticosteroids are of limited benefit in sunburn reactions but may help in polymorphous light eruption and photoallergic reactions
Since the face is often involved, close monitoring for corticosteroid side effects is recommended
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Aspirin may have some value for fever and pain of acute sunburn, as prostaglandins appear to play a pathogenetic role in the early erythema
Systemic corticosteroids in doses as described for acute contact dermatitis may be required for severe photosensitivity reactions
Hydroxychloroquine (5 mg/kg once daily) or immunosuppressives, such as azathioprine (50–300 mg once daily) or cyclosporine (3–5 mg/kg once daily) may be indicated in patients with chronic primary photodermatoses