Seafood Allergies Common for Adults
Tuna, Salmon, Shellfish Can Cause Serious Allergic Reactions
July 13, 2004 -- Shrimp, lobster, clams: Americans love
seafood. But many adults will develop a severe allergy to shellfish as well as
tuna and salmon.
Some 7 million Americans are thought to be affected, or 2.3% of
the population, according to a nationwide survey.
"This study showed that seafood allergy often develops in
adulthood, that most persons have multiple reactions, and that reactions often
include severe symptoms," writes lead researcher Scott H. Sicherer, MD,
with the Mount Sinai School of Medicine in New York.
His study appears in this month's issue of the Journal of
Allergy & Clinical Immunology.
Researchers define "seafood" as finned fish (tuna, cod,
salmon) and shellfish (shrimp, crab, lobster, scallops, clams, squid). An
allergic reaction to certain proteins in seafood can cause life-threatening
anaphylaxis -- a sudden, severe, potentially fatal reaction that results in low
blood pressure and throat swelling, making breathing difficult. Seafood
allergies can also cause a severe skin reaction or can trigger an asthma
According to the Food Allergy & Anaphylaxis Network,
food-induced anaphylaxis causes approximately 30,000 emergency room visits and
about 150 to 200 deaths each year in the U.S.
Despite the potential lethal nature of the reaction, few
studies have looked at exactly how common seafood allergy is, Sicherer
His nationwide telephone survey involved almost 15,000 adults
who answered detailed questions about finfish and shellfish -- identifying
individuals in their homes who had a seafood allergy, including positive
allergy skin test reaction or blood tests or an allergic reaction from eating
fish. The volunteers also produced information on the ages when these reactions
Sicherer found that both fish and shellfish allergies were more
commonly found among adults ages 40 to 60. Also:
- 6% of households had at least one person
with a seafood allergy.
- 3% of adults had any seafood allergies, compared with 0.6% of
- 4% of women had seafood allergies, compared with 2% of men.
- 40% of fish allergies and 60% of shellfish allergies began in
- For about 10% of those surveyed, the worst reactions were caused by
touching or smelling fish.
- Hives, swelling, difficulty breathing, and tightened throat were the most
- Salmon, tuna, catfish, and cod were the fish that most commonly caused
- Shrimp was the most common type of shellfish that caused reactions.
Only 9% of allergic people in Sicherer's study had a
prescription for epinephrine, which halts the reaction. Yet 16% reported having
been given the medication to halt an allergic reaction to fish in the past.
"This discrepancy highlights the need for improved awareness and education
about seafood allergies," he writes.
Since many people surveyed were reporting allergic reactions
but were not actually tested for a food allergy, his results may be somewhat
conservative, he says.