Dermatitis due to a sunscreen chemical, affecting the top but not the under surface of the arm Dermatitis of face, neck, arms and hands due to antiseptic in soap. Sometimes it is easy to recognise contact allergy and no specific tests are necessary. The open user test is used to confirm contact allergy to a cosmetic such as a moisturiser. The product under suspicion is applied several times daily for several days to a small area of sensitive skin. The inner aspect of the upper arm is suitable.
Contact allergy is likely if dermatitis arises in the treated area.
If you think you may have a contact allergy, consult a dermatologist to have patch tests performed. It is important to recognise how you are in contact with the responsible substance so that, where possible, you can avoid it. Ask your dermatologist to help. Contact allergy may disappear but often persists indefinitely. Net - Allergy and intolerance information resource.