Allergies to various inhalative
allergens are a serious problem in the bakery and confectionery industry. Sensitization to wheat flour and
enzymes such as
alpha-amylase are a frequent cause of
occupational asthma. Airborne egg
allergens have been reported as another cause of respiratory
allergy. We examined bakery and confectionery workers with respiratory symptoms due to egg
aerosols. Skin tests (SPT), scratch tests (ST), nasal provocation tests (NPT) and serological examinations (
IgE) were performed. Lung function was assessed by spirometry, and continuous registration of
aerosols and particulates as well as gravimetric sampling was done at the workplace. Four bakery and two confectionery workers intensively exposed to airborne
egg proteins suffered from
conjunctivitis and
rhinitis, four also from
asthma. Subsequently, three of these four workers reported symptoms after ingestion of food that contained egg. SPT with commercial egg white and egg yolk extracts were negative in four cases. Only two employees had clearly positive SPT to commercial egg
allergens and reacted also to wheat flour extracts. Scratch tests with native
egg proteins were positive in four employees. Specific
IgE to egg white and egg yolk were positive (CAP > or = 2) in three and in four cases, respectively, whereas they were negative in two cases. Elevated levels of specific
IgE to
lysozyme were detected in four employees. Two workers were sensitized to
lysozyme but not to other
egg proteins. The clinical relevance of egg sensitization was confirmed by continuous air sampling and by correlating the onset of the respiratory symptoms which were reflected by a significant decline (> or = 30%) of the forced one second capacity (FEV1) in two workers. Sieving of egg white
powder and an inadequate spray station for liquid eggs were identified as sources of excessive
allergen exposure. Bakery and confectionery workers exposed to airborne
egg proteins are at risk of developing
occupational asthma and subsequent nutritive
egg allergy. To our knowledge, these are the first cases of inhalative
egg allergy and subsequent nutritive
egg allergy reported in the literature, which we refer to as the "egg-egg syndrome" in analogy to the already known "bird-egg" and "egg-bird" syndromes.