What is the treatment for severe poison ivy using prednisone (corticosteroid)?

Treatment of Severe Poison Ivy Using Prednisone

For severe poison ivy dermatitis, oral prednisone starting at 1 mg/kg/day with a taper over at least 4 weeks is recommended to reduce symptoms and prevent rash return. 1

Clinical Presentation and Assessment

• Characteristic findings include:
  • Linear or streak-like pattern of redness, papules, and vesicles
  • Intense itching (pruritus) as the predominant symptom
  • Symptoms typically appear within days of exposure and can last up to 3 weeks
  • Severity proportional to area and duration of exposure 1

Treatment Algorithm for Poison Ivy

Immediate Management (First Hours After Exposure)

• Wash exposed areas with soap and water or commercial decontamination product
  • 100% effective if done immediately
  • 50% effective at 10 minutes
  • Only 10% effective at 30 minutes 1

Mild to Moderate Cases (< 30% Body Surface Area)

• Cool compresses for local symptom relief
• Oatmeal baths for symptomatic relief
• Topical corticosteroids (high-potency for body, low-potency for face)
• Oral antihistamines for sleep, though efficacy for pruritus is uncertain 1

Severe Cases (> 30% Body Surface Area or Involving Face/Genitals)

1. Oral Prednisone Regimen:

   • Start at 1 mg/kg/day 1
   • Continue for at least 14-21 days with a proper taper
   • Short courses (5 days) are associated with higher rates of symptom return and increased use of additional medications 2, 3

2. Recommended Taper Schedule:

   • Full dose for 5-7 days
   • Then gradual taper over 2-3 weeks
   • Total treatment duration of at least 14-21 days 3

Evidence for Longer Prednisone Course

Research shows that shorter courses of prednisone (less than 14 days) are associated with:

• Higher rates of return visits (30% increased risk) 3
• Greater use of additional medications (55.6% vs 22.7% with longer courses) 2
• Number needed to treat of only 3.05 patients to prevent additional medication use 2

Monitoring and Precautions

• For prednisone courses longer than 4 weeks:

  • Consider PJP prophylaxis
  • Provide calcium/vitamin D supplementation
  • Consider gastric protection
  • Monitor afternoon glucose for hyperglycemia 4

• Watch for signs requiring immediate medical attention:

  • Secondary infection
  • Difficulty breathing or swallowing
  • Rash not improving after 7-10 days of treatment 1

Important Cautions

• Avoid scratching as it can lead to secondary infection
• Avoid topical antihistamines, benzocaine, or other potential sensitizers that may cause additional allergic reactions
• Low-potency over-the-counter corticosteroids are often ineffective for moderate to severe cases 1
• Discontinue prednisone and seek medical attention if signs of systemic toxicity develop

Prevention of Future Exposures

• Learn to identify poison ivy/oak/sumac plants
• Wear protective clothing in high-risk areas
• Wash all potentially contaminated clothing, tools, and pets
• Consider commercial barrier creams if exposure is anticipated 1

The evidence strongly supports using a longer course (at least 14-21 days) of prednisone with proper tapering for severe poison ivy dermatitis to reduce symptom recurrence and the need for additional medications.