No immunological mechanism has been demonstrated to date. Asthma symptoms appear several hours after initial exposure to the risk, often during the night following contact. Rhinitis is often associated. J. Ind. Med. J. Ind. Med.
Most sufferers are atopic.
The sensitization period takes from 15 days to several years. The first cases which were reported involved subjects who worked in photographic studios. Asthma is sometimes preceded by eczema, urticaria and angioneurotic oedema. Rhinitis may be the only symptom for a long time or it may be immediately associated with asthma. It occurs at work and may continue during the night with or without a spasmodic cough.