Occupational immediate type allergy to soapnut and quillaja bark

A 58-year-old non-atopic chemical worker complained about work-related asthma and rhinoconjunctivitis about 4 years after exposure to quillaja bark and soapnut. Bronchial hyperresponsiveness was demonstrated after withdrawal of medication for 12 hours. Skin prick tests with extracts from quillaja bark and soapnut from the workplace were positive, but ImmunoCAP was positive only with quillaja bark, probably due to the low protein content of the extract from soapnut. Sensitizations to quillaja bark and soapnut, but not to saponin were demonstrated by immunoblot. An inhalation test with a dosimeter was positive with the soapnut extract. A link between disease and exposure was documented by serial measurements of exhaled nitric oxide at and off work, despite preventive measures. A diagnosis of occupational allergy due to quillaja bark and soapnut was made. Further exposure reduction was recommended.