Seafood contains a certain amount of histamine. Once histamine is absorbed by the human body and enters the immune system, it will cause allergies. Most people have enzymes that decompose histamine in their bodies, so there will be no allergies; However, it is worth noting that if the intake of histamine exceeds the tolerance range of human body, it may cause allergic poisoning. However, the so-called allergic poisoning and allergy are different.
People who are allergic to seafood will have symptoms as long as they consume a small amount of histamine; But allergic poisoning is due to excessive intake of histamine. Therefore, even normal people who contain histamine decomposing enzymes may still have allergic poisoning. Because the symptoms of allergic food poisoning and allergy are almost the same, misdiagnosis often occurs when seeking medical treatment, so patients should tell doctors in detail what they ate and how much they ate before making a correct diagnosis.
Seafood allergy poisoning occurs quickly, often after eating 0.5~ 1 hour, sometimes as long as 5 minutes, or as long as 4 hours. Symptoms are mild at onset, recovery is rapid, and death occasionally occurs. Often manifested as blushing, dizziness, headache, heartbeat, palpitation, chest tightness, shortness of breath, swelling of the face and lips, numbness of the tongue and limbs, nausea, vomiting, itchy skin and so on.
First, skin symptoms: skin congestion, eczema, itching, urticaria, vascular edema. These symptoms are most likely to appear in the face, neck, ears and other parts.
1, urticaria: itchy skin often appears first, then wheal, bright red or reddish and skin color, and a few patients have edematous erythema. Wind masses vary in size and shape, and the start time is uncertain. The wind mass gradually spread and merged into pieces. Due to dermal papillae edema, it can be seen that the epidermal hair follicle mouth is sunken downwards. The wind mass lasts for several minutes to several hours, and a few can last for a few days and disappear without leaving a trace. Rashes appear repeatedly in batches, especially at night. Wind masses are usually extensive or limited. Sometimes complicated with vascular edema, occasionally forming blisters on the surface of the wind mass. Some patients may be accompanied by nausea, vomiting, headache, head swelling, abdominal pain, diarrhea, and severe cases may also have chest tightness, discomfort, pallor, increased heart rate, weak pulse, decreased blood pressure, shortness of breath and other systemic symptoms.
2. Eczema: At first, the lesions were mostly dense miliary papules, papules or small blisters, and the basal flushing gradually merged into pieces. Due to scratching, papules, papules or blisters appear obvious punctate exudation and millet surface after scratching at the top, and the edge is unclear. If secondary infection, inflammation is more obvious, can form pustules, pus scabs, folliculitis, furuncle and so on. Consciously severe itching. Eczema caused by allergy may or may not be accompanied by gastrointestinal symptoms such as nausea, vomiting and diarrhea.
Second, gastrointestinal symptoms: nausea, vomiting, abdominal pain, bloating, diarrhea, mucus-like or watery stool, and some may have allergic gastritis, enteritis and celiac disease.
Third, nervous system symptoms: such as headache and dizziness. There may be more serious symptoms, such as a sharp drop in blood pressure, loss of consciousness, poor breathing and even anaphylactic shock.
What are the methods to prevent seafood allergy?
Most patients with seafood allergy are allergic because of excessive consumption of seafood. The reason of seafood allergy is that there are a lot of heterogeneous protein in seafood. These protein directly or indirectly activate immune cells, causing the release of chemical mediators, and then produce a series of complex biochemical reactions. When antibodies and antigens work together, people will have allergic symptoms.
1, avoid immature seafood: the bacteria in seafood are mainly Vibrio parahaemolyticus, etc. It has strong heat resistance and can only be killed above 80℃. In addition to bacteria brought by water, there may be parasitic eggs in seafood, as well as bacterial and viral pollution caused by processing.
Generally speaking, boiling water takes 4-5 minutes to completely sterilize. Therefore, we must be careful when eating unheated seafood such as "drunken crab", "raw sea urchin" and "sauce-fried seafood", and we must ensure the freshness and hygiene of fish when eating sashimi.
2, don't eat stale seafood: stale seafood may have a large number of reproductive bacteria, producing toxins, and the unsaturated fatty acids contained in it are also prone to oxidative rancidity. Stale shellfish will also produce more amines and free radicals, which pose a threat to human health.
After buying live shellfish, you can't keep them at home for too long. Cook them as soon as possible. People with allergies should pay special attention, because sometimes allergic reactions are not caused by seafood itself, but by substances in the process of protein decomposition of seafood.
3, do not drink with beer: it is best not to drink beer when eating seafood. Seafood such as shrimps and crabs will form uric acid after metabolism, and excessive uric acid will cause gout, kidney calculi and other diseases. If you eat a lot of seafood and drink beer at the same time, it will accelerate the formation of uric acid in the body.
Therefore, when eating a lot of seafood, don't drink beer, otherwise it will have a bad influence on your health.
4. Don't eat with fruit: Seafood such as fish, shrimp and crab is rich in nutrients such as protein and calcium. Fruit contains more tannic acid. If you eat fruit immediately after eating seafood, it will not only affect the human body's absorption of protein, but also make calcium in seafood combine with tannic acid in fruit to form insoluble calcium, which will stimulate the gastrointestinal tract and even cause abdominal pain, nausea, vomiting and other symptoms.
Therefore, it is best to eat seafood and fruit more than 2 hours apart.
5, do not drink tea: the reason why eating seafood is not suitable for drinking tea is similar to that for eating fruit. Because tea also contains tannic acid, it can also form insoluble calcium with calcium in seafood. Eating seafood before or after eating seafood will increase the chance of combining calcium with tannic acid. So it is best not to drink tea when eating seafood. Similarly, an interval of more than 2 hours is also the best.
6, shrimp avoid eating with vitamin C: arsenic, which is usually harmless to the human body, can be converted into toxic arsenic under the action of vitamin C.
7. Eat seafood carefully during taking medicine: According to your physique, for example, when some people are taking medicine, they must be very careful when eating seafood!