Fishy Food for Thought
- R. Robert Schellenberg
© Canadian Society of Allergy and Clinical Immunology 2005
Published: 15 June 2005
The article by Wu and colleagues in this issue describes an interesting case of asthma secondary to exposure to bloodworms in a laboratory setting. The use of bloodworms as a fish food has led to a number of differing manifestations dependent on the route of exposure. These include anaphylaxis, asthma, and urticaria/angioedema secondary to contact.
A person who worked in an office setting in our hospital was referred to me after three admissions to our emergency department for marked angioedema and inflammation of the right side of the face, chemosis of the right eye, and blurred vision with onset in the morning at work. She had no atopic history and had eaten no food on the day of one of the reactions. Only after persistent questioning regarding what she may have transferred from her hand to her face (she was right-handed) did she divulge that she fed the fish in her aquarium in the office. She did not know the source of the fish food, and I requested that she place a tiny amount on her forearm the following day. This produced a swelling of the entire forearm. The fish food was freeze-dried bloodworms.
Interestingly, at the annual meeting of the Canadian Society of Allergy and Clinical Immunology (CSACI) that same week, Dr. J. Roberts presented the case of a girl who had developed anaphylaxis after accidental ingestion of residual fish food that was on her hands when she was eating dinner. This individual had a striking reaction to a dilute preparation of the bloodworm fish food on skin testing and did not react to other fish food preparations.
Subsequent to these cases, a colleague mentioned additional cases of asthma symptoms in employees at the Vancouver Aquarium, where bloodworms are raised and processed as a food source.
The well-defined case presented in this issue and the others mentioned suggest that bloodworm may be a more common cause of allergic reactions than generally recognized and warrants consideration when the patient's history is reviewed.
R. Robert Schellenberg, MD, FRCP