What are the physical exam findings and treatment options for poison ivy?

Physical Examination Findings and Treatment of Poison Ivy

The primary physical exam findings of poison ivy include redness, papules, vesicles, and intense itching that typically start within days of exposure and can last up to 3 weeks. 1

Physical Examination Findings

Characteristic Skin Manifestations

• Redness (erythema) on exposed areas
• Papules and vesicles that may progress to bullae in severe cases
• Linear or streak-like pattern of lesions (highly characteristic)
• Pruritus (intense itching) is the predominant symptom
• Symptoms typically appear within days of exposure and can persist for up to 3 weeks 1
• Severity of symptoms is proportional to the area and duration of exposure 1

Distribution

• Most commonly affects exposed skin areas that came in contact with the plant
• May spread to other areas through transfer of urushiol oil
• Can affect any part of the body, including genitals in severe cases 2

Treatment Algorithm

Immediate Management (Within Hours of Exposure)

1. Wash exposed area with soap and water or a commercial decontamination product immediately (Class 1, Level B-NR recommendation) 1
   • Effectiveness decreases rapidly with time:
     • 100% removal if done immediately
     • 50% at 10 minutes
     • 25% at 15 minutes
     • 10% at 30 minutes 1

Treatment Based on Severity

Mild Cases (< 10% Body Surface Area)

• Topical treatments:
  • Cool compresses for symptomatic relief (Class 3, Level C-EO) 1
  • Oatmeal baths for symptomatic relief (Class 4, Level C-EO) 1
  • Hydrocortisone cream (FDA-approved for poison ivy) 3
  • Note: Over-the-counter topical steroids have uncertain efficacy (Class 2, Level B-NR) 1

Moderate to Severe Cases (> 10% BSA or significant symptoms)

• Continue all treatments for mild cases
• Consider systemic corticosteroids for extensive involvement 4
  • Oral prednisone starting at 1 mg/kg/day with a taper over at least 4 weeks 1
  • Short courses (5-7 days) may lead to rebound dermatitis

Severe Cases (> 30% BSA or systemic symptoms)

• Immediate medical attention required
• Systemic corticosteroids (oral or IV depending on severity)
• Consider hospitalization if facial or genital involvement, or if there are signs of secondary infection

Special Considerations

Cautions and Pitfalls

• Avoid scratching as it can lead to secondary infection and spread of the rash
• Antihistamines have uncertain efficacy for local symptoms (Class 5, Level C-EO) but may help with sleep 1
• Avoid using topical antihistamines, benzocaine, or other potential sensitizers that may cause additional allergic reactions
• Avoid hot water which can worsen itching
• Low-potency over-the-counter corticosteroids may be ineffective for moderate to severe cases 1

Prevention

• Learn to identify poison ivy: "Leaves of three, let them be"
• Wear protective clothing when in areas where poison ivy may grow
• Wash all potentially contaminated clothing, tools, and pets
• Consider commercial barrier creams if exposure is anticipated

When to Seek Medical Attention

• Rash covers more than 30% of body surface area
• Involvement of face, eyes, or genital areas
• Signs of secondary infection (increased pain, swelling, warmth, pus)
• Difficulty breathing or swallowing
• Rash does not improve after 7-10 days of home treatment

Poison ivy dermatitis is a self-limiting condition, but proper identification and prompt treatment can significantly reduce discomfort and prevent complications such as secondary infection.