Could You Have Anaphylaxis and Not Know It?

At first glance, an anaphylactic episode seems like it should be easily recognizable – airway swelling, difficulty breathing, possible fatality. However, in reality, with the statistics telling us that over 50% of patients presenting to hospital ERs with anaphylaxis are initially misdiagnosed with something else, it seems that identifying anaphylaxis is not so clear cut.

What is Anaphylaxis?

Anaphylaxis is a severe form of allergy that can be life-threatening. The most common triggers for anaphylaxis are insect venom such as bee stings, certain medications such as penicillin, and foods such as nuts, but theoretically it’s possible to be anaphylactic to anything, including cold temperatures.

Unlike a regular allergy, anaphylaxis affects multiple body systems, resulting in a wide variety of signs and symptoms such as:

• Hives or other skin symptoms
• Swelling, including of your mouth or throat
• Wheezing or coughing
• Chest tightness and difficulty breathing
• Hoarse voice
• Vomiting
• Stomach cramps and diarrhea
• Pale or red skin
• Low blood pressure
• Fainting

When respiratory and cardiovascular symptoms are not treated quickly, anaphylaxis can become fatal.

Why is Anaphylaxis Hard to Diagnose? 

The variable presentation of someone with anaphylaxis combined with the fact that it’s possible to be anaphylactic to a substance without realizing, can make the diagnosis of anaphylaxis challenging. For example, though skin reactions like hives and itching are common with anaphylactic reactions, 10-20% of anaphylaxis will present without these symptoms.

Someone experiencing anaphylaxis may be misdiagnosed with asthma instead, as having an anxiety or panic attack, food poisoning, or even vocal cord dysfunction. It is especially difficult if this is a person’s first anaphylactic episode and they have no other known history or allergies or anaphylaxis.

Anaphylaxis has no single test that can conclusively diagnose the condition on the spot. Specific blood tests for markers, such as histamine or another enzyme called tryptase, can help to support a diagnosis of anaphylaxis, but treatment cannot be delayed to wait for these results.

Are You at Risk for Anaphylaxis?

The possibility of you or a loved one being at risk of an anaphylactic reaction without even knowing it can be a scary thought. Fortunately, anaphylaxis is a relatively uncommon condition, with a global prevalence estimated to be 0.3-5.1%. In the US, approximately 225 deaths per year are attributed to anaphylaxis.

Factors that may increase the risk or severity of an anaphylactic reaction include:

• Having had a previous anaphylactic reaction
• Severe or uncontrolled asthma
• Co-existing cardiovascular disease
• Hayfever and eczema
• Thyroid disease
• Mast cell disorders, such as mastocytosis or hereditary alpha hypertryptasemia

Educating yourself to recognize the symptoms of anaphylaxis can help to improve outcomes if you should ever come across it, as well as being aware of the common anaphylaxis triggers.