On 23/7, a representative from the Quang Yen Medical Center reported that the symptoms appeared 4 hours after the meal, accompanied by abdominal pain and diarrhea. The patient did not experience skin rashes, a common symptom of allergies.

Test results confirmed anaphylactic shock, a severe allergic reaction that can be life-threatening if not treated promptly. The medical team followed Ministry of Health guidelines, administering adrenaline and respiratory and circulatory support. The patient is now out of critical condition and under close observation.

Doctor Vu Trong Tuan, Head of the Intensive Care and Toxicology Department, said this case exemplifies how anaphylactic shock can manifest with atypical symptoms, easily leading to misdiagnosis or being overlooked, especially without the presence of hives or itching.

Allergies occur when the body's immune system overreacts to a seemingly harmless substance, called an "allergen." Common allergens include foods (such as dried seafood, peanuts, and eggs), medications, chemicals, insect stings, weather, pollen, dust mites, and mold.

In severe cases (anaphylaxis), patients may experience symptoms such as shortness of breath, wheezing, flushing, dizziness, low blood pressure, abdominal pain, vomiting or diarrhea, and skin rashes or facial swelling, although these do not always occur. Without prompt treatment, patients can die from respiratory failure or circulatory arrest.

In mackerel, the two main substances that can cause reactions are histamine and parvalbumin. Histamine accumulates when mackerel is not stored properly, as bacteria convert histidine into histamine. Histamine is heat-stable, so cooking does not eliminate it. This condition is called scombrotoxin poisoning. Symptoms usually appear quickly, from a few minutes to a few hours after eating, and include flushing, itching, headache, nausea, and diarrhea. Although generally not dangerous, histamine poisoning causes significant discomfort.

Parvalbumin is a protein that causes true fish allergy, which is an immune response. This protein is also not destroyed by heat. People allergic to parvalbumin often have cross-reactions to other types of fish. Symptoms are more varied and can be severe, ranging from hives, difficulty breathing, and nausea to life-threatening anaphylactic shock.

Doctors advise people not to disregard any unusual symptoms after eating, taking medication, or exposure to chemicals or polluted air. Remember any foods, medications, or factors that have caused allergies in themselves or family members to take precautions.

To reduce risks, always store fresh fish properly. If you are allergic to fish, it is best to completely avoid mackerel and fish products. If you suspect an allergic reaction, seek immediate medical attention at the nearest facility.

Thuy Quynh