What is the treatment for cellulitis resulting from a wasp sting?

Treatment for Cellulitis Resulting from Wasp Sting

For cellulitis resulting from a wasp sting, treatment should include antibiotics active against streptococci and staphylococci, such as cephalexin or clindamycin, along with symptomatic management of pain and swelling. 1

Initial Assessment and Management

1. Differentiate between normal reaction and cellulitis:

   • Normal local reactions include pain, swelling, and itching that resolve within hours
   • Large local reactions include swelling >10cm that increases for 24-48 hours
   • True cellulitis presents with progressive erythema, warmth, tenderness, and swelling extending beyond the normal reaction area 2

2. Immediate sting management:

   • Remove stinger promptly by scraping or flicking (if present - wasps can sting multiple times) 1
   • Clean the area with soap and water to prevent infection 2
   • Apply cold compresses to reduce pain and swelling 1

Antibiotic Treatment for Cellulitis

First-line Treatment:

• Antibiotic therapy active against streptococci and staphylococci 1:
  • Cephalexin 500mg orally four times daily for adults 3
  • Clindamycin 300-450mg orally every 6 hours for more severe infections (especially for penicillin-allergic patients) 4

Duration of Treatment:

• 5 days of antibiotic therapy is recommended, but treatment should be extended if the infection has not improved within this time period 1

Supportive Care

1. Pain and inflammation management:

   • Oral analgesics (acetaminophen or NSAIDs) 2
   • Oral antihistamines to reduce itching 1
   • Cold compresses to reduce swelling 1

2. For severe swelling:

   • Consider a short course of oral corticosteroids (e.g., prednisone 40mg daily for 7 days) 1
   • Note: Corticosteroids should be used cautiously as they may mask signs of worsening infection

3. Elevation of affected area to reduce edema 1

When to Consider Hospitalization

Hospitalization is recommended if there is:

• Concern for deeper or necrotizing infection
• Systemic signs of infection (fever, tachycardia)
• Poor adherence to therapy
• Severe immunocompromise
• Failure of outpatient treatment 1

Important Distinctions

1. Allergic vs. Infectious Process:

   • Large local reactions are typically allergic in nature and occur within 24-48 hours
   • These are caused by allergic inflammation, not infection, and do not require antibiotics 1
   • True cellulitis requires antibiotic treatment

2. Special Considerations:

   • Some cases reported as "cellulitis" after wasp stings may actually be eosinophilic cellulitis (Wells syndrome), which responds better to steroids than antibiotics 5, 6
   • Secondary infections can occur and may require specific antibiotic coverage 6

Follow-up and Prevention

1. Monitor for improvement:

   • Symptoms should begin to improve within 48 hours of antibiotic initiation
   • If no improvement, consider alternative diagnoses or resistant organisms

2. Prevention of recurrence:

   • Identify and treat predisposing conditions (edema, venous insufficiency) 1
   • Education on insect avoidance strategies 1

Rare Complications to Consider

In unusual cases of cellulitis following wasp stings, rare pathogens have been reported, including fungal infections 7 and Nocardia 8. Consider these if standard treatment fails.