What is the treatment for poison ivy?

Treatment for Poison Ivy Dermatitis

Immediate Decontamination (Time-Critical)

Wash the exposed area with soap and water immediately—effectiveness drops precipitously from 100% removal at time zero to only 10% at 30 minutes. 1, 2, 3

• Remove all contaminated clothing, jewelry, and brush off any dry plant material before washing 1, 3
• If immediate washing is not possible, commercial decontamination products, hand cleaners, or dishwashing soap can still reduce symptoms by 55-70% when used within 2 hours of exposure 1, 2, 3, 4
• All three product types (commercial decontaminants, automotive hand cleaners like Goop, and dishwashing soap) show similar efficacy with no statistically significant differences 4

Treatment Algorithm by Severity

Mild to Moderate Dermatitis (≤30% Body Surface Area)

Apply moderate-to-high potency topical corticosteroids (mometasone furoate 0.1% ointment or betamethasone valerate 0.1% ointment) twice daily to affected areas. 2, 3

• Over-the-counter hydrocortisone has NOT been shown to improve symptoms in randomized trials and should not be relied upon 2, 3
• Add oral antihistamines: non-sedating second-generation agents (loratadine 10 mg daily) during daytime, or first-generation agents (diphenhydramine 25-50 mg or hydroxyzine 25-50 mg) at bedtime for sedation 2, 3
• Note that antihistamines primarily help with sleep rather than directly relieving itch—their efficacy for local pruritus is uncertain 2, 3
• If antihistamines fail, consider GABA agonists as second-line therapy: pregabalin 25-150 mg daily or gabapentin 900-3600 mg daily 2

Severe Dermatitis (>30% Body Surface Area or Limiting Self-Care)

Initiate systemic corticosteroids immediately with prednisone 0.5-1 mg/kg body weight for 7 days, followed by a mandatory weaning dose over 4-6 weeks. 5, 2, 3

• Continue high-potency topical corticosteroids to affected areas 2, 3
• Add oral antihistamines for symptomatic relief 2, 3
• The 4-6 week taper is critical—shorter courses risk rebound flare 2, 3

Supportive Care Measures

• Apply cool compresses to affected areas for symptomatic relief 1, 2, 3
• Consider oatmeal baths for widespread pruritus 1, 2, 3
• Use alcohol-free moisturizing creams or ointments twice daily, preferably containing 5-10% urea 2, 3
• Apply sunscreen SPF 15 to exposed areas every 2 hours when outside 2, 3

Critical Pitfalls to Avoid

Do not use short corticosteroid tapers—inadequate duration is the most common treatment failure. 2, 3

• Avoid frequent washing with hot water, which worsens symptoms 2, 3
• Avoid skin irritants including over-the-counter anti-acne medications, solvents, and disinfectants 2, 3
• Monitor for secondary bacterial infection: increased warmth, tenderness, purulent drainage, honey-colored crusting, or cellulitis all require antibiotic therapy 2, 3
• Do not delay washing after exposure—every minute counts, with effectiveness halving by 10 minutes 1, 2, 3

Expected Course

• Symptoms typically begin within days of exposure and last up to 3 weeks without treatment 3, 6, 7
• Approximately 50-75% of individuals react to urushiol, the allergenic compound 3