What is the treatment for poison ivy (Toxicodendron radicans) exposure?

Treatment for Poison Ivy Exposure

Immediate washing with soap and water is the most effective first step in treating poison ivy exposure, with effectiveness decreasing rapidly over time: 100% effective immediately after contact, 50% at 10 minutes, 25% at 15 minutes, and only 10% at 30 minutes. 1, 2

Immediate Management

1. Decontamination:

   • Wash exposed areas with soap and water or a commercial decontamination product as soon as possible 1
   • Remove and wash all potentially contaminated clothing, tools, and pets 2

2. Symptomatic Relief for Mild Cases:

   • Apply cool compresses to affected areas 1, 2
   • Take oatmeal baths for widespread exposure 1, 2
   • Apply topical hydrocortisone (FDA-approved for poison ivy relief) 3
     • Note: Low-potency OTC topical steroids like 2.5% hydrocortisone have uncertain efficacy 1, 2

Treatment Algorithm Based on Severity

Mild (Limited Area, Minimal Symptoms)

• Continue topical treatments as above
• Monitor for worsening symptoms

Moderate (Widespread or Uncomfortable)

• Moderate to high-potency topical corticosteroids 1, 2
• Oral antihistamines may help with sleep but have uncertain efficacy for itching 1, 2
• Monitor for 2 weeks; if symptoms worsen or don't improve, escalate treatment 1

Severe (Extensive Involvement, Intense Symptoms)

• Oral prednisone starting at 1 mg/kg/day with a taper over at least 4 weeks 2
• For courses longer than 4 weeks, consider PJP prophylaxis, calcium/vitamin D supplementation, and monitor for hyperglycemia 2
• Temporarily interrupt normal activities if limiting self-care 1

When to Seek Medical Attention

• Rash covering more than 30% of body surface area
• Involvement of face, eyes, or genital areas
• Signs of secondary infection
• Difficulty breathing or swallowing
• Rash not improving after 7-10 days of home treatment 2

Important Cautions

• Avoid scratching as it can lead to secondary infection 2
• Avoid topical antihistamines, benzocaine, or other potential sensitizers that may cause additional allergic reactions 2
• The rash itself is not contagious, but the oil can be spread before washing 1
• Without continued exposure, symptoms typically resolve within 1-3 weeks 4, 5

Prevention

• Learn to identify poison ivy (three leaflets per leaf, "leaves of three, let it be")
• Wear protective clothing when in areas where poison ivy may be present
• Consider commercial barrier creams if exposure is anticipated 2

Poison ivy dermatitis presents as a characteristic linear or streak-like pattern of lesions with redness, papules, vesicles, and intense itching that typically starts within days of exposure 2, 5. The severity of symptoms is proportional to the area and duration of exposure 1.