Review Question - QID 214208

This patient is presenting after eating new foods with a raised, blanchable/pruritic rash (urticaria), abdominal pain, nausea, and vomiting, which meets criteria for anaphylaxis.

Anaphylaxis is a type I hypersensitivity reaction (IgE mediated) that presents with severe allergic symptoms that affect at least 2 different organ systems. Patients can present with cutaneous symptoms (such as hives and angioedema), respiratory symptoms (such as wheezing), GI symptoms (such as abdominal pain, nausea, and vomiting), and cardiovascular symptoms (such as hypotension and tachycardia). Any patient meeting criteria for anaphylaxis with at least 2 organ systems involved should immediately be given intramuscular epinephrine. Other medications that can be given after epinephrine include steroids, diphenhydramine, and famotidine.

Figure A is the characteristic rash of urticaria with a raised, blanchable rash that is pruritic.

Incorrect Answers:
Answer 2: Celiac disease occurs after exposure to gluten and can present with abdominal pain, diarrhea, and dermatitis herpetiformis, which is a pruritic herpes-like rash. It increases the risk of bowel wall lymphoma. It would not present with sudden, severe symptoms and is instead a chronic disease.

Answer 3: Scombroid is caused by eating fish that have been stored inappropriately and presents with a peppery/metallic taste in the mouth and flushing, warmth, pruritus, diarrhea, dizziness, and a urticarial rash. Treatment is generally diphenhydramine for symptom control.

Answer 4: Urticaria presents with pruritic wheals after exposure to an allergen. It can be treated with medications such as diphenhydramine and avoidance of the inciting antigen. Though this patient has an urticarial rash, the involvement of 2 or more organ systems suggests a diagnosis of anaphylaxis.

Answer 5: Urticaria multiforme is a benign cutaneous hypersensitivity reaction that presents with dermatographism and wheals, with a dusky center that appears similar to erythema multiforme. Patients often complain of pruritus.

Bullet Summary:
Anaphylaxis is a systemic inflammatory response to an antigen with at least 2 organ systems involved.