ANAPHYLAXIS: WHAT IT IS, HOW TO DIAGNOSE IT, SYMPTOMS, TRIGGERS, AND ACTION PLAN

Anaphylaxis is a severe, rapid, and life-threatening allergic reaction that requires immediate medical treatment. Without quick action, it may progress to airway obstruction, shock, and even death. Early recognition and prompt injection of epinephrine are the key to survival.

1. What Is Anaphylaxis?

Anaphylaxis is a systemic allergic reaction involving multiple organs, triggered by sudden release of mediators (histamine, tryptase, leukotrienes) from mast cells and basophils.

It can occur:

• Within seconds to minutes after exposure

• Sometimes up to 1–2 hours later

• Rarely, it can be biphasic, meaning symptoms return after initial recovery

Anaphylaxis must always be considered a medical emergency.

2. How to Diagnose Anaphylaxis

Diagnosis is clinical, based on symptoms after a likely exposure to an allergen. Per internationally accepted criteria (NIAID/WAO), anaphylaxis is likely when any one of the following occurs:

Criterion 1:

Acute onset (minutes to hours) with:

• Skin or mucosal involvement (hives, flushing, swelling) AND

• Respiratory symptoms OR

• Drop in blood pressure

Criterion 2:

Two or more of the following after exposure to likely allergen:

• Skin/mucosal signs (hives, angioedema)

• Respiratory symptoms

• Cardiovascular symptoms (hypotension, fainting)

• Persistent GI symptoms (vomiting, abdominal cramps)

Criterion 3:

Hypotension after exposure to a known allergen:

• Adults: systolic < 90 mmHg or >30% drop

• Children: low age-specific blood pressure

Key point:

You do NOT need skin symptoms to diagnose anaphylaxis.

Some cases present only with breathing difficulty or circulatory collapse.

3. What Are the Symptoms of Anaphylaxis?

Symptoms may involve any organ system.

A. Skin (most common)

• Hives (urticaria)

• Flushing

• Itching

• Angioedema (swelling of lips, eyelids, tongue)

B. Respiratory

• Shortness of breath

• Wheezing (asthma-like)

• Stridor / throat tightness

• Hoarse voice

• Difficulty swallowing

• Drooling (in children)

C. Cardiovascular

• Hypotension

• Dizziness

• Lost consciousness

• Rapid or weak pulse

D. Gastrointestinal

• Nausea

• Vomiting

• Severe abdominal pain

• Diarrhea

E. Neurological

• Feeling of “impending doom”

• Confusion

• Sudden fatigue

Fatal cases often begin with breathing difficulty, not skin symptoms.

4. What Are the Main Triggers of Anaphylaxis?

A. Foods

The most common cause in children and young adults:

• Peanuts

• Tree nuts

• Milk

• Eggs

• Wheat

• Soy

• Shellfish

• Fish

• Sesame

• Kiwi, peach, spices (less common)

B. Insect Venom

• Bees

• Wasps

• Hornets

• Fire ants

C. Medications

• Penicillins

• Cephalosporins

• NSAIDs (ibuprofen, aspirin)

• Muscle relaxants (anesthesia)

• Contrast media

• Chemotherapy drugs

D. Latex

E. Exercise-Induced Anaphylaxis

Often triggered by:

• Exercise alone

• Exercise + food (e.g., wheat, seafood)

F. Unknown (Idiopathic)

Up to 20% of cases have no identifiable trigger.

5. Action Plan: What to Do in Case of Anaphylaxis

STEP 1: Inject Epinephrine Immediately

• Use EpiPen, Auvi-Q, or Emerade.

• Inject into the mid-outer thigh (through clothing if needed).

• Dose:

  • Adult: 0.3 mg

  • Child <30 kg: 0.15 mg

Never wait for symptoms to “get worse.” Epinephrine is safe; delay is dangerous.

STEP 2: Call Emergency Services (911)

Tell them:

“This is anaphylaxis. Epinephrine has been given.”

Even if symptoms improve, the patient must be monitored for recurrence.

STEP 3: Lie the Patient Down

• If breathing difficulty: keep sitting up slightly

• If hypotensive: lie flat with legs elevated

• Do NOT allow the patient to stand or walk

Sudden standing can cause fatal collapse.

STEP 4: Give Second Epinephrine Dose if Needed

• If symptoms persist after 5–10 minutes, use a second auto-injector.

STEP 5: Adjunctive Treatments

These do NOT replace epinephrine, but may help:

• Antihistamines

• Inhaled bronchodilators (Ventolin)

• Corticosteroids

But the only lifesaving treatment is epinephrine.

6. Preventing Anaphylaxis

A. Identify the Trigger

Through:

• Clinical history

• Skin prick testing

• Specific IgE testing

• Component-resolved diagnostics

• Oral food challenge (gold standard)

B. Avoid the Trigger

• Strict avoidance of foods

• Cross-contamination education

• Wearing medical alert bracelets

• Allergy-safe school/work protocols

C. Always Carry Two Epinephrine Auto-Injectors

D. Have a Personalized Anaphylaxis Action Plan

Including:

• Symptoms checklist

• When to inject epinephrine

• Emergency contacts

• Steps for school/work caregivers

E. Consider Immunotherapy

For:

• Venom allergy

• Some food allergies (oral immunotherapy)

Conclusion

Anaphylaxis is a serious but treatable emergency: recognition, rapid epinephrine injection, and immediate medical attention save lives. With proper diagnosis, avoidance strategies, and a clear action plan, patients can live safely and confidently.