toxicity and toxicology

Sgombroid syndrome

The sgombroid syndrome - also known as HPF ( Histamine Fish Poisoning ) - is an allergic-like foodborne illness caused by the ingestion of altered fish products.

Responsible for this syndrome is the presence of the so-called sgombrotoxin, a mixture of histamine and other amines (such as putrescine and cadaverine) produced by the decomposition of some amino acids, present in the tissues of fish products. Histamine, in particular, derives from histidine, while cadaverine and putrescine derive respectively from the decarboxylation of lysine and ornithine.

We speak of a mackerel syndrome because the concentrations of free histidine are greater in the fish species belonging to the Scombridae family, such as tuna and mackerel; in general this amino acid is abundant in all migratory species. However, it must be considered that histamine intoxication is not just typical of fish consumption, as it is present in various foods (especially fermented ones and canned meats); this should also be taken into account if the fish is consumed together with other foods rich in histamine (sauerkraut, soy sauce, tamari, etc.) or able to enhance its action (alcohol, acidic foods, fermented cheeses).

Histamine is a physiologically present substance in our body, where it plays an important role in the regulation of the immune system. Large amounts of histamine are released during allergic reactions and are responsible for symptoms such as itching, rashes and breathing difficulties. Therefore, the ingestion of foods rich in histamine can trigger a symptomatology similar to that of an allergic reaction . It should however be pointed out that there are significant differences in individual tolerance to histamine contained in food; some people, defined " histamine-sensitive ", more easily suffer problems following the ingestion of foods rich in this amine. Our body has the ability to inactivate food-borne histamine in the intestine, assisted also by the subsequent liver filter; probably the effectiveness of these mechanisms contributes to establishing the different degree of individual tolerance to foods rich in histamine.

Symptoms of the sgombroid syndrome appear rapidly (from a few minutes to 2-3 hours, on average 90 minutes) after ingestion of the food and include headache, conjunctival hyperemia, burning mouth, erythema (diffuse redness of the skin), hives, nausea, vomiting, diarrhea and abdominal cramps. Respiratory difficulties, palpitations, hypotension and myocardial ischemia may occur in the most severe forms of mackerel syndrome, however rare.

The eventual treatment in case of severe poisoning by sgombroide involves the use of antihistamines, including diphenhydramine and cimetidine. Only rarely may bronchodilators be needed. In general, however, the mackerel syndrome produces mild manifestations that rapidly regress.

The prevention of the mackerel syndrome requires compliance with the correct methods of conservation and product management (HACCP); at home it is recommended to:

  • check the freshness of the product and eliminate the altered one;
  • correct management of the cold chain: use any thermal bags for transport from the place of purchase to the place of consumption or storage;
  • avoid refreezing thawed products;
  • respect the expiry dates shown in the packages;
  • after opening, consume any canned products during the day (alternatively immediately transfer the unused product into food containers and keep it in the fridge)
  • avoid leaving fish-based dishes and fishing products at room temperature for a long time before consumption.