First-Line Treatment for Poison Ivy
For mild to moderate poison ivy dermatitis, topical corticosteroids (such as hydrocortisone) are the first-line treatment, while severe cases (affecting >30% body surface area, facial/genital involvement, or significantly limiting daily activities) require oral corticosteroids with prednisone 1-2 mg/kg/day (maximum 60 mg daily) for 5-7 days followed by a 2-3 week taper. 1
Immediate Decontamination (If Recent Exposure)
- Wash the affected area with soap and water immediately if exposure occurred within hours 1
- Any surfactant-based cleanser is effective—even standard dishwashing soap provides 56-61% protection when used promptly after exposure 2
- Commercial decontamination products offer no significant advantage over inexpensive household soaps 2
Treatment Based on Severity
Mild to Moderate Cases (Local Treatment)
Topical corticosteroids are sufficient when the rash is limited in extent and not interfering with daily function 3, 4:
- Hydrocortisone cream/ointment applied to affected areas for relief of itching and inflammation 5
- The FDA approves topical hydrocortisone specifically for poison ivy dermatitis 5
- Expected resolution within 1-3 weeks with local treatment alone 3, 4
Severe Cases (Systemic Treatment Required)
Oral prednisone is indicated when any of the following are present 1:
- >30% body surface area affected
- Facial or genital involvement
- Symptoms significantly limiting self-care activities
Dosing protocol 1:
- Prednisone 1-2 mg/kg/day (maximum 60 mg daily)
- Continue full dose for 5-7 days
- Then taper gradually over 2-3 weeks
The extended taper is critical—shorter courses risk rebound dermatitis 1
Adjunctive Symptomatic Measures
- Cool compresses to affected areas provide immediate relief 1
- Oatmeal baths may offer additional comfort 1
- Over-the-counter antihistamines have limited evidence but may help nighttime itching 1
Monitoring and Follow-Up
- Expect improvement within 2-3 days of starting systemic corticosteroids 1
- Reassess diagnosis if no improvement by day 3—consider alternative diagnoses or secondary infection 1
- Watch for worsening symptoms despite appropriate treatment, which warrants additional medical evaluation 1
Common Pitfalls to Avoid
Do not use short corticosteroid courses (such as standard 5-6 day tapers) for severe poison ivy—these frequently result in rebound dermatitis requiring retreatment 1. The full 2-3 week taper is necessary because the allergic reaction can persist longer than typical inflammatory conditions.
Do not rely on topical corticosteroids alone for severe cases—they are insufficient when significant body surface area is involved 1.