Formaldehyde is the American
Contact Dermatitis Society Contact
Allergen of the Year for 2015. The exposure is widespread, and contact
allergy might be difficult to suspect in the individual
dermatitis patient. The relevance of contact
allergy to
formaldehyde might also be difficult to evaluate. Recently, however, several studies have been performed aimed at enhancing the patch test technique and evaluating the clinical relevance of contact
allergy to
formaldehyde. The patch test concentration of
formaldehyde has been recommended by the European Environmental
Contact Dermatitis Research Group to be 2.0%, that is, the dose of 0.60 mg/cm (wt/vol) instead of 1.0%, which is the concentration previously used for the baseline series in most countries. Without causing any more
irritant reactions, the patch test concentration of 2.0% detects twice as many contact
allergies and enables the diagnosis of
formaldehyde-allergic patients who otherwise would have been missed. The studies that underpin the decision were performed in Europe and partly in the United States. The Finn Chamber patch test system was used. The
allergen dose per area was kept uniform with a micropipette. This report describes the background for routinely using
formaldehyde 2.0% instead of 1.0% and for using a micropipette when applying the test
solution.