Wild Dispatch

Benadryl Isn’t Enough: How to Treat Anaphylaxis in the Wilderness

By Dr. Michael Gerst, DO | CEO & Founder, PrepEM Wild

You’re deep in the backcountry when your hunting partner gets stung by a yellow jacket. Within minutes, their face is flushed, they’re covered in hives, and they’re clearing their throat constantly. They tell you it’s just a bad reaction and reach for the Benadryl in their pack.

As an ER physician, I can tell you exactly what happens next if you rely solely on that antihistamine: their airway will begin to swell shut, their blood pressure will plummet, and by the time you realize they need an EpiPen, it might be too late to reverse the shock.

Anaphylaxis is an acute, rapidly evolving, multi-systemic allergic reaction. Without immediate, aggressive treatment, it is fatal. In the wilderness, where a 911 call means a helicopter rescue hours away, understanding the difference between a mild allergic reaction and true anaphylaxis—and knowing exactly when to use epinephrine—is a non-negotiable survival skill.

Allergic Reaction vs. Anaphylaxis: The Critical Difference

The biggest mistake people make in the field is waiting too long to use epinephrine because they aren’t sure if the reaction is "bad enough" yet. Here is the clinical distinction:

• A Mild Allergic Reaction involves only ONE body system—typically the skin (hives, itching, redness) or the nasal passages (sneezing, runny nose).
• Anaphylaxis involves TWO OR MORE body systems, or isolated severe respiratory/cardiovascular symptoms.

Note: If a patient has a known severe allergy (e.g., to peanuts) and is exposed, any sudden drop in blood pressure or difficulty breathing is considered anaphylaxis immediately—even without hives.

The Wilderness Anaphylaxis Protocol

When anaphylaxis hits, you have minutes to act. Most anaphylactic deaths occur within the first hour after antigen exposure. According to the Wilderness Medical Society (WMS) Clinical Practice Guidelines, this is the exact protocol you must follow:

1. Inject Epinephrine Immediately: Do not wait to see if it gets worse. Inject 0.3 mg of epinephrine (standard adult EpiPen dose) into the outer thigh muscle. It can be injected straight through clothing. Hold the injector firmly in place for 3-10 seconds depending on the brand instructions.
2. Position the Patient: Have them sit or lie down comfortably. If they are showing signs of shock (pale, dizzy, weak pulse), lay them flat and elevate their legs to keep blood flowing to vital organs. Do not let them stand up suddenly.
3. Administer Adjunctive Meds (After Epi): Once the epinephrine is in, you can give antihistamines (like Benadryl) to help with hives and itching, and corticosteroids if available. But remember: these are secondary. They do not replace epinephrine.
4. Monitor and Prepare to Re-Dose: Epinephrine wears off quickly—often in 10 to 15 minutes. If symptoms do not improve, or if they return after initially getting better, you must administer a second dose of epinephrine 5 to 15 minutes after the first. This is why anyone with a known severe allergy should carry at least two auto-injectors in the backcountry.
5. Evacuate Immediately: Anaphylaxis requires an immediate emergency evacuation. Even if the patient feels 100% better after the EpiPen, up to 20% of patients experience a "biphasic reaction"—a second, potentially fatal wave of anaphylaxis that can hit 8 to 11 hours later without any additional exposure.

Tested in the Field

When you are miles from definitive care, hesitation kills. Don't wait for a mild reaction to become a life-threatening airway obstruction. If you see two body systems involved, or any sign of respiratory distress, hit them with the EpiPen. It is always better to administer epinephrine unnecessarily than to wait too long when it is truly needed.

Prepare Safely. Respond Boldly.