What is the treatment for poison ivy complicated by cellulitis (cellulitis)?

Treatment for Poison Ivy Complicated by Cellulitis

For poison ivy dermatitis complicated by cellulitis, treatment should include oral antibiotics effective against streptococci (such as cephalexin, dicloxacillin, or amoxicillin) combined with topical or systemic corticosteroids for the poison ivy component. 1, 2

Diagnosis and Assessment

When evaluating a patient with suspected poison ivy complicated by cellulitis, look for:

• Linear or streak-like vesicular rash characteristic of poison ivy dermatitis 2
• Signs of cellulitis: spreading erythema, warmth, tenderness, and swelling beyond the poison ivy rash 1
• Systemic symptoms: fever, tachycardia, or elevated white blood cell count 1
• Predisposing factors: breaks in skin from scratching the poison ivy rash 1

Treatment Algorithm

Step 1: Determine Severity

• Mild to moderate: Localized cellulitis without systemic symptoms
• Severe: Extensive cellulitis, systemic symptoms, immunocompromised patient

Step 2: Antibiotic Selection

For mild to moderate cellulitis:

• First-line: Oral antibiotics active against streptococci 1
  • Cephalexin 500 mg four times daily
  • Dicloxacillin 500 mg four times daily
  • Amoxicillin-clavulanate 875/125 mg twice daily
  • Clindamycin 300-450 mg four times daily (if penicillin-allergic)

For severe cellulitis:

• Hospitalization for parenteral antibiotics 1
  • Cefazolin 1-2 g every 8 hours
  • Nafcillin/oxacillin 2 g every 6 hours
  • Vancomycin 15 mg/kg every 12 hours (if penicillin-allergic or MRSA suspected)

Step 3: Poison Ivy Treatment

• Topical corticosteroids: High-potency for localized areas 2, 3
• Systemic corticosteroids: For extensive poison ivy dermatitis 2, 3
  • Prednisone 40 mg daily for 7 days with taper over 2-3 weeks

Step 4: Supportive Measures

• Elevate affected area to reduce edema 1
• Cool compresses to relieve itching
• Wash area thoroughly with soap and water to remove any remaining urushiol oil 3
• Treat any underlying conditions (e.g., tinea pedis, venous insufficiency) 1

Duration of Treatment

• Antibiotics: 5 days for uncomplicated cellulitis, extending if no improvement 1
• Corticosteroids: Typically 2-3 weeks with tapering dose 2

Special Considerations

MRSA Coverage

MRSA is an unusual cause of typical cellulitis unless there is:

• Purulent drainage
• Evidence of abscess
• Penetrating trauma
• Known MRSA colonization

In these cases, consider adding coverage with trimethoprim-sulfamethoxazole, doxycycline, or clindamycin 1.

Hospitalization Criteria

Consider inpatient treatment if:

• Signs of systemic toxicity (fever, hypotension, altered mental status)
• Extensive or rapidly spreading infection
• Immunocompromised host
• Failed outpatient therapy
• Poor adherence expected 1

Prevention of Recurrence

• Identify and avoid poison ivy plants 4
• Wear protective clothing when in areas with poison ivy 3
• Wash skin immediately after potential exposure 3
• For recurrent cellulitis (3-4 episodes per year), consider prophylactic antibiotics 1

Common Pitfalls

• Misdiagnosing cellulitis when only poison ivy dermatitis is present
• Failing to treat both components of the condition
• Not elevating the affected area, which is crucial for improving cellulitis
• Stopping antibiotics too early before resolution of cellulitis
• Inadequate dosing of corticosteroids for extensive poison ivy dermatitis