From the Guidelines
Cutaneous symptoms, such as urticaria or angioedema, are not always present with anaphylaxis, occurring in only the majority of patients, with 10% to 20% of cases having no cutaneous manifestations. While anaphylaxis typically presents with multiple organ system involvement, including respiratory symptoms (wheezing, shortness of breath), cardiovascular symptoms (hypotension, tachycardia), and cutaneous manifestations, the absence of skin findings does not rule out anaphylaxis 1. This is important to recognize because waiting for skin manifestations to appear before diagnosing anaphylaxis could delay critical treatment. Some key points to consider include:
- Anaphylaxis can involve various organ systems, including the respiratory, cardiovascular, gastrointestinal, and cutaneous systems 1.
- The signs and symptoms of anaphylaxis can vary, but typically include a combination of symptoms such as flushing, pruritus, urticaria, angioedema, nasal congestion, throat pruritus, laryngeal edema, stridor, choking, wheeze, cough, dyspnea, cramping, abdominal pain, nausea, emesis, diarrhea, dizziness, tachycardia, hypotension, and hypotonia 1.
- Treatment with epinephrine should not be delayed if other symptoms suggest anaphylaxis, even in the absence of cutaneous symptoms 1. Anaphylaxis should be suspected in any acute onset illness with typical respiratory compromise, cardiovascular symptoms, or persistent gastrointestinal symptoms, especially after exposure to a likely allergen.
From the FDA Drug Label
The signs and symptoms associated with anaphylaxis include flushing, apprehension, syncope, tachycardia, thready or unobtainable pulse associated with hypotension, convulsions, vomiting, diarrhea and abdominal cramps, involuntary voiding, airway swelling, laryngospasm, bronchospasm, pruritus, urticaria or angioedema, swelling of the eyelids, lips, and tongue. The manifestation that is not always present with anaphylaxis is not specified in the provided drug labels.
- The labels list various signs and symptoms associated with anaphylaxis, but do not indicate which ones may be absent in some cases. 2
From the Research
Manifestations of Anaphylaxis
- Cutaneous symptoms are not always present with anaphylaxis, as some patients (10-30%) can present without cutaneous findings 3
- The lack of skin/mucosa involvement can lead to misdiagnosis or delayed diagnosis of anaphylaxis 3
- Clinical manifestations of anaphylaxis can include cutaneous and cardiovascular symptoms, but more than 20% of patients did not present with cutaneous symptoms 3
Common Symptoms of Anaphylaxis
- Urticaria, difficulty breathing, and mucosal swelling are the most common symptoms of anaphylaxis 4
- Anaphylaxis can present with a wide range of clinical manifestations and variable progression, making diagnosis challenging 5
Diagnosis and Treatment
- Anaphylaxis is a clinical diagnosis, but plasma tryptase and urinary histamine levels are often elevated, allowing diagnostic confirmation 6
- Epinephrine is the essential antianaphylactic drug in the pharmacologic treatment, and should be applied intramuscularly 7
- The diagnosis of anaphylaxis is purely clinical, and laboratory tests are of no help in the acute situation 7