What is the appropriate treatment for a wasp sting?

Treatment of Wasp Stings

For wasp stings, treatment should include immediate removal of the stinger (if present), cleaning the area with soap and water, and applying ice or cool compresses to reduce pain and swelling, with topical corticosteroids and oral antihistamines for local reactions, while severe systemic reactions require immediate epinephrine administration. 1, 2

Initial Management of Local Reactions

1. First steps:

   • Remove the stinger if present (wasps can sting multiple times, unlike bees)
   • Clean the area thoroughly with soap and water
   • Apply ice or cool compresses for 10-15 minutes to reduce pain and swelling

2. Topical treatments:

   • Apply topical corticosteroids to reduce inflammation
   • Consider calamine lotion to relieve itching
   • For elderly patients, use emollients with high lipid content 1

3. Oral medications:

   • Non-sedating antihistamines (e.g., cetirizine, loratadine, fexofenadine) to reduce itching
   • Acetaminophen or NSAIDs for pain relief
   • Avoid sedating antihistamines in elderly patients due to increased risk of falls and confusion 1

Management of Severe Local Reactions

• For large local reactions (extending >10 cm from sting site):
  • Continue topical corticosteroids
  • Oral antihistamines
  • Consider a brief course of oral corticosteroids in severe cases
  • Elevate the affected limb if applicable
  • Monitor for 48-72 hours for signs of infection 1

Management of Systemic Reactions (Anaphylaxis)

Anaphylaxis is a medical emergency requiring immediate treatment:

1. Immediate administration of epinephrine:

   • Adult dose: 0.3-0.5 mg intramuscularly into anterolateral thigh
   • Can be repeated every 5-15 minutes if symptoms persist 1, 2

2. Additional measures:

   • Ensure airway patency
   • Administer oxygen if available
   • Place patient in supine position with legs elevated (unless respiratory distress)
   • IV fluids for hypotension
   • Monitor vital signs

3. Secondary medications:

   • H1-antihistamines (for urticaria and pruritus)
   • H2-blockers (as adjunctive therapy)
   • Corticosteroids (to prevent biphasic or protracted reactions)
   • Bronchodilators for bronchospasm

Signs and Symptoms to Monitor

1. Local reactions:

   • Pain, redness, swelling at sting site
   • Itching
   • Local heat

2. Signs of secondary infection:

   • Increasing redness, warmth, pain beyond 48 hours
   • Purulent drainage
   • Fever
   • Spreading redness beyond immediate bite area 1

3. Signs of systemic reaction (require immediate medical attention):

   • Skin: generalized urticaria, angioedema, flushing
   • Respiratory: dyspnea, bronchospasm, laryngeal edema
   • Cardiovascular: hypotension, tachycardia, syncope
   • Gastrointestinal: nausea, vomiting, abdominal cramps, diarrhea
   • Neurological: anxiety, dizziness, confusion 2

Prevention and Follow-up

1. Prevention measures:

   • Use DEET-containing repellents (10-30%)
   • Wear protective clothing, especially during dusk and dawn
   • Avoid bright colors and strong scents
   • Use screens on windows and doors
   • Avoid areas with standing water
   • Remove nests with professional help 1

2. Follow-up recommendations:

   • For local reactions: monitor for 48-72 hours
   • For systemic reactions: referral to allergist-immunologist
   • Consider venom immunotherapy for those with history of systemic reactions
   • Patients with history of systemic reactions should carry self-injectable epinephrine and know how to use it 1

Special Considerations

• Rare but serious complications may include:

  • Rhabdomyolysis (muscle breakdown) 3
  • Cerebral infarctions 4, 5
  • Acute renal failure 3
  • These complications are more likely with multiple stings

• High-risk populations:

  • Elderly patients (more susceptible to adverse medication effects)
  • Patients with mastocytosis (prone to very severe reactions) 6
  • Individuals with previous systemic reactions

• When to seek emergency care:

  • Any signs of systemic reaction
  • Multiple stings (estimated lethal dose is approximately 20 stings/kg) 7
  • Stings in mouth or throat (risk of airway compromise)
  • Persistent or worsening symptoms despite treatment