Research – Two Case Reports of Scombroid in Singapore: A Literature Review



Scombroid is a foodborne illness that results from eating improperly handled fish. Due to a disruption in the cold chain, these fish have high histamine levels. As a result, scombroid presents with allergy-like symptoms but is not really an allergy per se. Cases have been reported in many countries.

Here, we report two cases of a 48 and 17-year-old father and son in Singapore who developed symptoms suggestive of scombroid after eating tuna imported from Vietnam delivered by an internationally known supply company. The diagnosis was confirmed by elevated histamine levels measured in the culprit fish product. We discuss the pathophysiology, signs, symptoms, and management of scombroid.


Scombrotoxin fish poisoning (SFP) also known as scombroid poisoning, scombrotoxicosis, or histamine fish poisoning is a foodborne illness that results from the consumption of fish that has been improperly handled between the time it is caught and the time it is cooked [1]. The word “scombroid” is derived from Scombridae which is a family of dark-fleshed fish consisting of species such as mackerel and tuna. However, non-scombroid fishes such as mahi-mahi, salmon, and sardine have also been implicated in scombroid poisoning [2].

Scombroid poisoning is very common. A 2013 report from the United States estimated over 35,000 cases resulting in 162 hospital admissions between 2000 and 2009 [3]. Scombroid cases have also been reported from countries such as Australia [4], the Netherlands [5], Israel [6], Colombia [7], and many others.

Inappropriate storage, resulting in disruption of the cold chain, of the fish leads to bacterial enzymatic conversion of free histidine into histamine. This is due to the action of bacterial histamine decarboxylase (HDC), usually by mesophilic bacteria such as Clostridium perfringensMorganella morganii, etc. As a result, high levels of histamine are usually found in the culprit seafood item [8]. Whether histamine is the only constituent of “scombrotoxin” is unclear. Nevertheless, the symptomatology is essentially that of histamine toxicity. It is considered an atypical foodborne illness as the main symptoms are not gastrointestinal and also because it is not due to contamination of the product.

While mostly self-limiting and mild, there have been reports of life-threatening scombroid poisoning. A previously healthy young woman developed hypotension needing vasopressors with ST depressions [9] while another scombroid poisoning was complicated by acute pancreatitis [10]. Some cases were severe enough to need ICU admissions. A recent narrative discussed acute coronary syndromes (ACS) associated with scombroid. Of note, there is a potential of hemodynamic failure in the acute stage, even in apparently healthy people [11].

Closer to home, in September 2016, the Agri-Food and Veterinary Authority (AVA) of Singapore issued a recall order on a batch of canned tuna imported from Thailand under a common food brand. This was reported in various newspapers such as The Straits Times and The Independent. In one issue of the Singapore Food Agency’s Food Safety Bulletin in 2018, there was a segment on scombroid. Interestingly, however, a PubMed search was conducted and while we found a case of pufferfish poisoning reported in 2013 [12] and a report of stonefish poisoning in 2009 [13], we found no reports of scombroid poisoning in Singapore. We report two confirmed cases of scombroid poisoning who are from the same household who presented to our hospital after consuming tuna for dinner.

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