EXPOSURE TO GASEOUS FORMALDEHYDE INDUCES IGE-MEDIATED SENSITIZATION TO FORMALDEHYDE IN SCHOOLCHILDREN

Background Children attending a primary school showed symptoms such as headache, cough, rhinitis and epistaxis. Assessment of specific IgE t o formaldehyde gave positive results in some children. Objective Was I gE-mediated sensitization as well as symptoms in children associated w ith formaldehyde exposure at school? Methods Sixty-two 8-year-old chil dren attending: three forms at a primary school were investigated. Ind oor formaldehyde concentrations were measured in classrooms of both sc hools (one frame construction with particleboard used extensively as p anelling vs a brick building) which were consecutively attended. Asses sment of specific IgE to formaldehyde was done in all children. Childr en were transferred to a brick building and 3 months later specific Ig E to formaldehyde in pupils showing initially elevated radioallergosor bent test (RAST) values reassessed. In all children symptoms were eval uated by questionnaire before and 3 months after changing school. Resu lts In the school panelled with particleboard the World Health Organiz ation (WHO) threshold for formaldehyde of 0.050 ppm was crossed in two classrooms (0.075 ppm and 0.069 ppm) whereas in one classroom 0.043 p pm was found. RAST classes of greater than or equal to 2 were found in three children, two of them attending the classroom with 0.075 ppm fo rmaldehyde. Elevated RAST classes of greater than or equal to 1.3 were found in another 21 pupils. Thirty-eight pupils as well as 19 control children showed RAST classes in the normal range of less than or equa l to 1.2. Headache, nose bleeding, rhinitis, fatigue, cough, dry nasal mucosa and burning eyes were found in the affected children. There wa s a good correlation between symptoms and the formaldehyde concentrati ons in the classrooms. However, elevated IgE levels to formaldehyde di d not correlate with symptoms. Formaldehyde concentrations in the clas srooms of the brick built school were 0.029 ppm, 0.023 ppm and 0.026 p pm. After transferral specific IgE to formaldehyde decreased significa ntly from 1.7 +/- 0.5 to 1.2 +/- 0.2 (P < 0.002) as did the incidence of symptoms. Conclusion Gaseous formaldehyde, besides its irritant act ion, leads to IgE-mediated sensitization. As children are more sensiti ve to toxic substances than adults, threshold levels for indoor formal dehyde should be reduced for children.