A 67-year-old patient developed systemic reactions after application o
f a formaldehyde-containing tooth tilling. She had a clearly positive
RAST result for formaldehyde, whereas skin prick testing and patch tes
ts were negative. Sensitization to formaldehyde appears to have occurr
ed 1 year previously. Induction of formaldehyde allergy may represent
a major complication during dental treatment, and assessment of specif
ic IgE should be considered in patients at risk.