Sunscreen chemicals allergy
Contact or photo-allergy to chemical UV filters.
About sunscreen chemicals allergy
Chemical UV filters in sunscreens, such as benzophenones (oxybenzone), octocrylene and cinnamates, can cause skin allergy in two ways. They may produce an ordinary delayed, type IV allergic contact dermatitis, appearing 12 to 72 hours after use, or a photo-allergic reaction, in which the chemical only triggers a rash after the skin is exposed to sunlight. Both are uncommon relative to how widely sunscreens are used, but they are worth recognising, particularly in people who apply sunscreen frequently or who have sun-sensitive skin conditions.
The rash is itchy and red, sometimes scaly or blistered, appearing where the product was applied. A useful clue to photo-allergy is that the reaction is worst on sun-exposed areas such as the face, neck, backs of the hands and forearms, while skin covered by clothing is spared. The reaction can be confusing because people may assume they are simply sunburning or that their skin cannot tolerate the sun, when the sunscreen ingredient is the real trigger.
Diagnosis uses patch testing and, for suspected photo-allergy, photopatch testing, both carried out by a dermatologist. Management means identifying the responsible filter and choosing sunscreens that avoid it; mineral (physical) sunscreens based on zinc oxide or titanium dioxide are often better tolerated. Emollients and, if advised, topical steroids settle flares. See your GP or a dermatologist if a rash appears on sun-exposed skin despite using sunscreen.
Common triggers
- Sunscreen chemicals and products containing it
Symptoms
- Red, itchy rash (contact dermatitis)
- Dry, cracked or scaly skin
- Blistering or weeping in severe cases
- Burning or stinging where skin met the trigger
Avoidance & management
- Avoid skin contact with the trigger
- Wear gloves or use barrier creams
- Choose products labelled free from the allergen
- Rinse skin promptly after contact
- Use emollients or prescribed steroid creams
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.