From the Guidelines
If you're experiencing vomiting after an allergic reaction to shellfish, seek immediate medical attention as this could be part of a severe allergic reaction (anaphylaxis) and administer epinephrine via an auto-injector if available and prescribed by a doctor. While waiting for help, take an antihistamine like diphenhydramine (Benadryl) at a dose of 25-50mg if you can keep it down, as suggested by general medical guidelines 1. For persistent vomiting, anti-nausea medications such as ondansetron (Zofran) 4-8mg or promethazine (Phenergan) 12.5-25mg may help, but these require a prescription. It's crucial to stay hydrated by taking small sips of clear fluids once vomiting subsides and avoid solid foods until you can tolerate liquids for several hours. The vomiting occurs because your immune system releases histamine and other chemicals when exposed to shellfish allergens, causing inflammation and irritation of your digestive tract, a mechanism understood through the study of anaphylaxis 1.
Key Considerations
- The first-line treatment for anaphylaxis, which can include vomiting as a symptom, is epinephrine administered intramuscularly, as emphasized in the 2020 practice parameter update on anaphylaxis 1.
- Antihistamines and glucocorticoids are commonly used in anaphylaxis management, although their role is not as clearly defined as that of epinephrine, according to the grading of recommendations, assessment, development, and evaluation (GRADE) analysis 1.
- For future prevention, always carry an epinephrine auto-injector (EpiPen) if you have a known shellfish allergy, wear a medical alert bracelet, and carefully check food ingredients to avoid accidental exposure, as advised for patients at risk of anaphylaxis 1.
Management and Prevention
- Patients and caregivers should be trained in recognizing anaphylaxis symptoms and using an epinephrine auto-injector, highlighting the importance of education in anaphylaxis management 1.
- After treating anaphylaxis with epinephrine, it's essential to seek medical attention in an emergency department to assess if additional interventions are needed, underscoring the need for prompt medical evaluation 1.
From the Research
Treatment for Vomiting after an Allergic Reaction to Shellfish
- The primary treatment for an allergic reaction to shellfish, including vomiting, is avoidance of the allergen 2, 3.
- In the event of an allergic reaction, management may involve administering high concentration oxygen and intramuscular adrenaline 4.
- There are also therapeutic options being explored, such as production of hypoallergenic shrimp, use of immunotherapy with modified allergens, probiotics, and Chinese herbal formulations 2.
- Additionally, a recombinant hypoallergenic tropomyosin has been developed, which may provide a new avenue in the treatment of shellfish allergy 5.
- It is essential to note that shellfish allergy can cause severe reactions, including anaphylaxis, and prompt medical attention is necessary in such cases 3, 6, 4.