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Photosensitive Dermatosis — SCE Dermatology MCQ

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ModeratePhotobiologyPhotosensitive DermatosisSCE Dermatology

A 30-year-old woman presents with a photosensitive eruption. Photoprovocation testing shows abnormal reactions to both UVA and UVB with a markedly reduced MED to both. She also has a positive patch test to Compositae mix. What is the single most important management advice?

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Correct answer: E — Strict broad-spectrum photoprotection (UVA and UVB) and allergen avoidance

When both UVA and UVB sensitivities are present with co-existing contact allergy (common in chronic actinic dermatitis), strict broad-spectrum photoprotection is essential. This includes high-factor broad-spectrum sunscreen (SPF 50+), UVA-protective clothing (UPF-rated), behavioural modifications (seeking shade, avoiding peak UV hours), and avoidance of the identified contact allergen (Compositae). Window film blocking UVA may be beneficial indoors/in cars as UVA penetrates glass. The combination of photodermatosis and contact allergy is well-described in chronic actinic dermatitis. Oral immunosuppression (Ciclosporin, Azathioprine) may be needed for severe photosensitive dermatoses unresponsive to photoprotection.

Reference: BAD 2019 Photodermatoses Guidelines