FS04.1 Formaldehyde allergy – clinically relevant threshold reactions

Abstract

The objective of the study was to establish eliciting threshold concentrations of diazolidinyl urea (Germall II)– derived formaldehyde in formaldehyde and/or in diazolidinyl urea – sensitive patients, using a leave‐on face cream formulation in a repeated open application test (ROAT) applied to different anatomical regions.150 patients with known formaldehyde allergy were reviewed for inclusion in the study. 108 patients were contacted and in 65 patients the formaldehyde sensitisation was reconfirmed by a patch test. Four groups of 10 formaldehyde allergic subjects were exposed to 0.05%, 0.15%, 0.3% and 0.6% diazolidinyl urea, corresponding to approximately 50, 100, 200 and 400 ppm free formaldehyde, respectively.Additional 10 individuals allergic to the formaldehyde donor – diazolidinyl urea itself – were exposed to 0.15% diazolidinylurea, corresponding to approximately 100 ppm free formaldehyde and 10 healthy non‐allergic individuals were exposed to 0.6% of diazolidinylurea (approximately 400 ppm free formaldehyde).A ROAT was performed in a scheduled sequence: upper arm, neck and face.Contact allergy reactions were elicited in 39 out of 58 formaldehyde‐sensitive and in 5 out of 7 diazolidinyl urea‐sensitive individuals.Elicitation responses were dose‐ and anatomical region – dependent.No reactions were observed at the lowest dose, suggesting that an elicitation threshold was attained in the study.