What should you know about medication and sun sensitivity?

Medication-related sun sensitivity may cause an exaggerated sunburn-like reaction on exposed skin, with redness, warmth, tenderness, itching or blistering. Some reactions appear soon after exposure; others can resemble a rash and may linger. The reaction can depend on the medicine, dose, skin type and amount of ultraviolet exposure. A drug rash may also occur without sunlight, so the timing and distribution help a clinician work out what is happening.

Check the leaflet or ask a pharmacist whether your medicine increases sun sensitivity. Use shade, protective clothing, a broad-spectrum sunscreen suitable for your skin, and avoid deliberate tanning. Reapply sunscreen as directed and remember that reflected light can reach exposed areas. Do not stop an essential medicine on your own; discuss alternatives or timing with the prescriber. Photograph a new rash and record when the medicine and sun exposure occurred.

Contact a clinician for a new or persistent rash after starting medicine, especially if it spreads or blisters. Get urgent help for facial swelling, breathing difficulty, skin peeling, painful mouth or eye involvement, or feeling faint.

Ask whether your medicine is photosensitising, which areas need protection, and whether the reaction could be a drug rash requiring a change in treatment.