Why does sun allergy cause sun sensitivity?

Polymorphic light eruption is a delayed skin reaction to sunlight, usually involving ultraviolet exposure. The immune system reacts in the exposed skin, causing redness, itching, small bumps, or patches. The appearance can differ between people and even between episodes. Areas covered during darker months may be more reactive when suddenly exposed.

The rash often affects the chest, arms, or neck while sparing areas that receive regular exposure, although patterns vary. Medicines, contact products, and other light-sensitive conditions can cause similar symptoms, so an unusual pattern deserves assessment.

Seek shade, use closely woven clothing and a broad-spectrum sunscreen, and increase exposure gradually rather than staying in strong sun for long periods. Reapply sunscreen according to its label, especially after sweating or swimming. Keep affected skin cool and avoid scratching. A clinician can recommend treatment for itch or discuss preventive options when flares recur.

Get medical advice for widespread blistering, facial swelling, breathing difficulty, eye involvement, fever, or a rapidly worsening reaction. Arrange a review if the rash follows minimal light exposure, appears under clothing, starts after a new medicine, scars, or repeatedly disrupts daily activities.

Ask whether the timing and distribution fit polymorphic light eruption, whether any medicine or product may increase light sensitivity, and which sunscreen, clothing, or treatment plan is appropriate for your skin.