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How Long After Eating Shellfish Can An Allergic Reaction Occur (And Why)?

Exact Answer: 30 Minutes To 1 Hour

Eating a shellfish might sound like having a good meal to people. However, very few people know that shellfish can cause severe allergic reactions in the body which can even be lethal in acute cases of allergic reaction. 

How Long After Eating Shellfish Can An Allergic Reaction Occur?

Type Of ShellfishTime
Crustaceans1 to 2 hours
Mollusks30 minutes to 1 hour

The type of allergic reactions caused in the body and the time it takes for an allergic reaction to occur in the body when shellfish is consumed by the person depends upon several different factors such as the bow allergy a person is to shellfish, amount of shellfish, and other such factors. However, there is one major factor that determines the time for how long it will take for an allergic reaction to occur after eating the factor. That time determining factor is the type of shellfish consumed.

There are majorly two types of shellfish, that are, crustaceans, and the other one is mollusks. The crustaceans shellfish consists of shrimps, crabs, and lobsters. On the other hand, mollusks consist of shellfish such as clams, mussels, oysters, scallops, squid, octopuses. In most cases, crustaceans do not cause more allergic reactions in the body as compared to mollusks. However, it also depends upon the allergic history of the person.

If a person consumes crustaceans, which includes, shrimps, crabs, and lobsters, then it takes more time to no time for allergic reactions to occur as compared to a person eating a mollusk. In most cases, it takes about a minimum of 1 hour to a maximum of 2 hours for allergic reactions to occur after eating crustaceans as shellfish.

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While on the other hand, if a person consumes mollusks, which include clams, mussels, oysters, scallops, squid, and octopus, it takes comparatively more time for an allergic reaction to occur. In most cases, it takes about a minimum of 30 minutes to a maximum of 1 hour for allergic reactions to occur after eating mollusks as shellfish.

Why Does It Take That Long For An Allergic Reaction To Occur After Eating Shellfish?

The major reason why a shellfish causes such severe allergic reactions in the body is that almost every type of shellfish has certain proteins in it which are not synthesized by the body. Instead, the immune system of the body considers these proteins to be foreign material that is introduced into the body.

As a result, every person with a good immune system recognizes the protein as a foreign material when exposed to it through the consumption of shellfish. Moreover, to protect the body from the considered foreign invader, the immune system prepared itself to fight against it.

During the procedure of preparing the body to fight a foreign invader, the immune system prepares some certain type of antihistamines to fight against the particular foreign invader. The same procedure happens in the case of the consumption of shellfish as well. When a person consumes a shellfish, his or her immune system prepares a certain type of antihistamines and releases it in the blood to fight off the protein introduced in the body.

For most of the people who are not allergic to antihistamines or are not allergic to that particular type of antihistamine that is produced by the immune system in the blood to fight against the protein of the shellfish, no allergic reactions occur in the body. 

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On the other hand, people who are generally all allergic to antihistamines or are allergic to that particular type of antihistamine that is produced by the immune system in the blood to fight against the protein of the shellfish, multiple allergic reactions occur in their body, which can range from nominal allergic reactions to severe allergic reactions in acute cases.

Conclusion

Consuming a shellfish can cause several allergic reactions in the body such as stomach pain, nausea, vomiting, indigestion, wheezing, diarrhea, shortness of breath, hoarse voice, cough, swelling in mouth and throat, discoloration in skin, itchiness, and dizziness.

However, in acute cases, there could be severe allergic reactions caused in the body after consumption of the shellfish such as anaphylaxis, trouble in breathing, swelling in the throat, and rapid heartbeat. This majorly happens in case if the person is highly allergic to shellfish.

References

  1. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2222.2010.03513.x
  2. http://higiene.unex.es/Bibliogr/InfIntox/IJFM0081.pdf