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674 CMAJ, April 3, 2012, 184(6) © 2012 Canadian Medical Association or its licensors
References
1. Jantschitsch C, Kinaciyan T, Mana M, et al. Severe
scombroid sh poisoning: an underrecognized der-
matologic emergency. J Am Acad Dermatol 2011;
65:246-7.
2. Hungerford JM. Scombroid poisoning: a review.
Toxicon 2010;56:231-43.
3. O’Connor MM, Forbes GM. Scombroid poisoning:
not sh allergy. Aust N Z J Med 2000;30:520.
4. Morrow JD, Margolies GR, Rowland J, et al. Evi-
dence that histamine is the causative toxin of scom-
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5. Attaran RR, Probst F. Histamine sh poisoning: a
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45
Five things to know about …
Scombroid poisoning
Piero Stratta MD, Guido Badino PhD
1
Scombroid poisoning is a common
form of food poisoning related to
sh ingestion
Scombroid poisoning occurs after the
ingestion of fresh, canned or smoked sh
with high histamine levels due to im -
proper processing or storage. First de -
scribed in conjunction with sh in the
suborder Scombroidea (e.g., tuna and
mackerel), it has since been described
with other dark-eshed sh (e.g., sar-
dines and ancho vies). Scombroid poison-
ing is one of the most common causes of
morbidity associated with sh intake.1,2
Scombroid poisoning is not an allergy
Allergic reactions typically affect one person who has a history of allergy to the
implicated food item. However, with scombroid poisoning, more than one per-
son, often with no history of allergies, may be affected.3Histamine produced by
the decarboxylation of histidine in the muscle of the sh is primarily responsible
for the condition. The decarboxylation process is induced by enzymes produced
by primarily enteric gram-negative bacteria (e.g., Morganella morganii,
Escherichia coli, Klebsiella species and Pseudomonas aeruginosa) found in the
sh’s cutis and intestines.1,2
Competing interests: None declared.
This article has been peer reviewed.
Afliations: From the Department of Nephrol-
ogy and Transplantation (Stratta), Amedeo Avo-
gadro University, Novara, Italy; and the Depart-
ment of Animal and Human Biology (Badino),
University of Torino, Torino, Italy
Correspondence to: Dr. Piero Stratta, piero.stratta
@med.unipmn.it
CMAJ 2012. DOI:10.1503/cmaj.111031
3
Symptoms are that of histamine
poisoning
Symptoms of scombroid poisoning
include ushing, rash, urticaria (gen-
erally widespread erythema, usually
lacking wheals), palpitations, head -
ache, dizziness, sweating, and burn-
ing of the mouth and throat. Gas-
trointestinal symptoms can in clude
abdominal cramps, nausea, vomiting
and diarrhea. Broncho spasm, respira-
tory distress and vasodilatory shock
have also been described. Symptoms
begin within 10 to 90 minutes after
eating the implicated sh. The rash
lasts 2–5 hours, and the other symp-
toms usually disappear within 3–36
hours. The diagnosis is often clinical
and can be conrmed by measure-
ment of histamine in incriminated
spoiled food. Determination of the
patient’s histamine level in plasma or
the level of histamine metabolites
(e.g., N-methylhistamine) in urine can
also support the diagnosis.4
Histamine does not change the smell
or appearance of the affected sh
Scombroid poisoning is frequently
misdiagnosed.5Because histamine
does not alter the organoleptic quality,
the sh may seem normal. However,
elevated histamine levels can occur in
sh owing to improper refrigeration
before processing or to storage of the
sh at room temperature after cook-
ing. Therefore, the appearance, taste
and smell of the sh are poor guides
as to the presence of histamine. Hista-
mine is heat-stable and remains pres -
ent after cooking, freezing, canning or
smoking. Outbreaks are most common
in summer.1,2
Treatment involves antihistamines
and supportive care
Most instances of scombroid poison-
ing are self-limited. However, if the
patient has symptoms severe enough
to re quire treatment, rapid-acting
antihistamines (usually H1-receptor
antagonists) are commonly used,
along with supportive care tailored to
the symptoms. Adrenalin and corti -
co steroids are generally not indi-
cated.1,2,5 To prevent further instances
of poisoning, public health authori-
ties should be notied to investigate
the source and remove the impli-
cated product from distribution.