Wasp Sting Reactions: Local vs. Systemic – When to Act Fast

Wasps (yellow jackets, hornets, paper wasps) can sting repeatedly. Reactions range from trivial to fatal.

Normal Local Reaction

• Immediate sharp pain, burning.
• Red welt, swelling ≤5 cm, resolves in hours.
• Itching, warmth.

Large Local Reaction (LLR)

• Swelling >10 cm, crossing joints, peaks 48–72 hrs, lasts 5–10 days.
• Not allergic (IgE-mediated); late-phase inflammatory.
• Treatment: Ice, elevation, oral antihistamine, short-course oral prednisone (if severe).
• Risk of future anaphylaxis: ~5–10% (vs 1% general).

Systemic Allergic Reaction (Anaphylaxis) – MEDICAL EMERGENCY

• Skin: Generalized hives, flushing, angioedema (lips, eyelids, tongue).
• Respiratory: Wheeze, stridor, dyspnea, throat tightness.
• Cardiovascular: Hypotension, tachycardia, syncope, shock.
• GI: Nausea, vomiting, diarrhea, cramping.
• Neurologic: Dizziness, confusion, sense of doom.

Onset: usually <30 min. Can be biphasic (recurrence 8–72 hrs later).

Immediate Action for Anaphylaxis

1. Epinephrine IM (anterolateral thigh) – 0.3 mg (0.15 mg <30 kg). Auto-injector (EpiPen, Auvi-Q, generic). Repeat q5–15 min if needed.
2. Call 911. Say "anaphylaxis."
3. Supine position (or semi-recumbent if breathing difficult), legs elevated.
4. O₂, IV fluids, albuterol, H1/H2 blockers, steroids – in EMS/ED.
5. Observe 4–6 hrs (biphasic risk).

Long-Term Management

• Refer to Allergist/Immunologist.
• Venom Immunotherapy (VIT): 98% effective. 3–5 yr course.
• Carry 2 auto-injectors always. Medical ID.
• Avoidance: no barefoot, cover food, screens, professional nest removal.