What should you know about a UV sensitivity rash?

A rash may appear on sun-exposed skin as redness, bumps, itching, burning, blisters or swelling. Some reactions begin soon after exposure; others can appear later or last after the skin is covered. A medicine or fragranced product can make skin more sensitive to UV, while heat, sweat and friction can create a different-looking eruption.

The appearance alone cannot identify the cause. Contact dermatitis may follow a product, drug rash may follow a medicine, and conditions such as atopic dermatitis, psoriasis, heat rash, intertrigo, ringworm or scabies can sometimes be mistaken for a UV reaction. A clinician may ask about timing, distribution, new products, medicines and whether covered skin is affected.

Move out of direct sunlight, cover the area with closely woven clothing and use shade while the reaction settles. Avoid new cosmetics, fragranced products and unapproved home remedies on the rash. Use a bland moisturiser if it does not sting, and cool compresses may ease discomfort. Do not stop a prescribed medicine without checking with the prescriber, even if you suspect it triggered the reaction.

Take a photo and note the exposure time, products used and medicines taken. A clinician can decide whether you need a topical treatment, a medicine change or testing for another cause. Do not deliberately re-expose the rash to test it.

Get urgent help for trouble breathing, faintness, swelling of the lips or tongue, rapidly spreading hives or extensive blistering. Seek prompt medical review for fever, severe pain, pus, eye involvement, mouth sores or skin that is peeling broadly. Arrange an appointment when the rash repeatedly follows light exposure, persists despite protection or began after a new medicine.

Could my medicines or skincare products be increasing UV sensitivity? Does the distribution fit a light reaction or another rash? Should I change or pause anything, and how can I protect my skin? What symptoms would mean I need urgent review?