What is the treatment for poison ivy exposure?

Treatment for Poison Ivy Exposure

For poison ivy dermatitis, immediately wash the exposed area with soap and water, apply high-potency topical corticosteroids (such as mometasone furoate 0.1% or betamethasone valerate 0.1% ointment) twice daily for mild-to-moderate cases, and initiate systemic prednisone 0.5-1 mg/kg daily with a 4-6 week taper for severe cases. 1

Immediate Decontamination (Time-Critical)

The effectiveness of decontamination drops precipitously with time, making immediate action essential:

• Wash with soap and water immediately after contact to remove 100% of urushiol oils, but effectiveness plummets to 50% at 10 minutes, 25% at 15 minutes, and only 10% at 30 minutes. 1, 2
• Remove all contaminated clothing, jewelry, and materials before washing, and brush off any dry plant material first. 1, 2
• If immediate washing is not possible, commercial decontamination products, hand cleaners, or dishwashing soap can still produce 55-70% symptom reduction even when used up to 2 hours after exposure. 1, 2

Treatment Algorithm by Severity

Mild-to-Moderate Dermatitis

• Apply moderate-to-high potency topical corticosteroids (mometasone furoate 0.1% ointment or betamethasone valerate 0.1% ointment) twice daily to affected areas. 1
• Over-the-counter hydrocortisone is FDA-approved for poison ivy but has NOT been shown to improve symptoms in randomized trials and should not be relied upon. 1, 3
• Add oral antihistamines: non-sedating second-generation antihistamines (loratadine 10 mg daily) during daytime, or first-generation antihistamines (diphenhydramine 25-50 mg or hydroxyzine 25-50 mg) at bedtime for sedation. 1
• Note that antihistamines may primarily help with sleep rather than directly relieving local itching. 1, 2

Severe Cases (Widespread Involvement, Facial/Genital Involvement)

• Initiate systemic corticosteroids immediately with prednisone 0.5-1 mg/kg body weight for 7 days, followed by a weaning dose over 4-6 weeks. 1
• Continue high-potency topical corticosteroids to affected areas concurrently. 1
• Add oral antihistamines for symptomatic relief. 1
• Critical pitfall: Ensure the corticosteroid taper is long enough (4-6 weeks minimum) to prevent rebound flare, which is common with shorter courses. 1

Supportive Care Measures

• Apply cool compresses to affected areas for symptomatic relief. 1, 2
• Consider oatmeal baths for widespread symptoms, though evidence supporting this is limited. 1, 2
• Use alcohol-free moisturizing creams or ointments twice daily, preferably with urea-containing (5-10%) moisturizers. 1
• Avoid frequent washing with hot water and skin irritants, including over-the-counter anti-acne medications, solvents, or disinfectants. 1
• Apply sunscreen SPF 15 to exposed areas every 2 hours when outside. 1

Critical Warning Signs Requiring Antibiotics

Monitor for secondary bacterial infection, which requires antibiotic therapy:

• Increased warmth and tenderness at the site 1
• Purulent drainage 1
• Honey-colored crusting 1
• Cellulitis (spreading erythema, warmth, swelling) 1

Expected Course

• Symptoms typically begin within days of exposure and last up to 3 weeks without treatment. 1
• Approximately 50-75% of individuals react to urushiol, the allergic compound in poison ivy. 1, 4