What should you know about extreme sun allergy?

Polymorphic light eruption is a common form of sun allergy. It may cause itchy red bumps, small blisters or patches on the neck, chest, arms or backs of the hands after sunlight. The face may be less affected in people whose skin has adapted to regular exposure. Reactions can vary between people and may be confused with heat rash, contact dermatitis or a medicine-related light sensitivity. A clinician considers the timing, distribution and any new medicines or skincare products.

Sun sensitivity means skin reacts more readily to ultraviolet light; it does not by itself identify one specific condition. Mention reactions that recur each sunny season, follow brief exposure, or occur through windows or after medication changes.

Limit direct sun during the strongest daylight, use closely woven clothing, a wide-brimmed hat and broad-spectrum sunscreen, and reapply as directed. Introduce outdoor exposure gradually rather than trying to build a tan. A clinician may recommend a short course of topical corticosteroids for an established flare. For recurring symptoms, supervised narrowband UVB phototherapy may help the skin adapt before a high-exposure season.

Arrange a medical review for a widespread, recurrent or severe rash, especially if it follows a new medicine. Seek urgent help for facial swelling, breathing difficulty, faintness, extensive blistering, fever or involvement of the eyes or mouth.

Ask whether the pattern fits sun allergy, whether a medicine or product is increasing light sensitivity, which protection is suitable, and whether preventive phototherapy or prescription treatment is appropriate.