Approach
The main goal of management is to prevent exposure to poison ivy, oak, and sumac by patient education and by wearing protective clothing.[2][6][24]
Many barrier creams have been developed and tested.[25] A randomized, double-blind study of seven different commercially available barrier creams found three products that offered a statistically significant reduction in dermatitis severity.[26]
Immediate treatment postexposure
Urushiols are easily degraded in water, so it is helpful to wash with soap and water immediately after exposure. Only 50% of urushiols can be removed by washing at 10 minutes, 25% at 15 minutes, and 10% at 30 minutes.[27]
Forceful, unidirectional washing of exposed areas with a damp washcloth and liquid soap under hot running water is recommended to reduce or prevent toxicodendron dermatitis.[28]
A number of commercial sprays (e.g., Tecnu®, Zanfel®) may act to bind urushiol and prevent its absorption, if the product is applied to the skin soon after exposure.[29][30]
Mild dermatitis
First-line treatment is with topical corticosteroids. The potency of the topical corticosteroid used is determined by the severity and location of the dermatitis. Topical corticosteroids are rated on a potency scale from 1 (highest potency) to 7 (lowest potency).
Mild dermatitis usually responds to 2 to 15 days' therapy with a moderate-potency topical corticosteroid (e.g., betamethasone valerate). Higher-potency corticosteroids can be tried if this does not result in significant clinical improvement. Low-potency corticosteroids (e.g., hydrocortisone) are recommended for thin-skinned areas such as skin folds, neck, and face.
A topical calcineurin inhibitor can be used if corticosteroids are contraindicated or instead of a corticosteroid in a particularly thin-skinned area. Topical tacrolimus is likely to be more effective in poison ivy dermatitis than pimecrolimus, which may not be of sufficient potency, except in the mildest of cases.[31]
Moderate dermatitis
Moderate dermatitis usually responds to 7 to 21 days' therapy with a potent topical corticosteroid (e.g., fluticasone). An ultra-potent topical corticosteroid can be tried if needed; clinicians should weigh the potential benefits and harms of higher-potency corticosteroids in patients with thin skin. A topical calcineurin inhibitor may be used as an alternative to a higher-potency topical corticosteroid.
If symptoms deteriorate or fail to improve with topical therapies, second-line treatment is systemic oral corticosteroids. The dose needs to be tapered but if reduced too early may result in a flare-up of the dermatitis. If this occurs, increase the dose again and taper more slowly.
Severe dermatitis
Severe dermatitis may require treatment with up to a 3-week tapering dose of systemic oral corticosteroids.[32][33][34] Shorter courses may suffice if there is a delay between symptom onset and treatment. Systemic oral corticosteroids are used in combination with potent topical corticosteroids (or a topical calcineurin inhibitor). If oral corticosteroids are reduced too quickly, a flare-up of the dermatitis may occur, requiring a return to the higher dose and a slower tapering regime. If compliance with oral therapy is difficult, an intramuscular injection of triamcinolone may be used.
Repeated exposure and chronic dermatitis
If repeated exposure cannot be avoided (e.g., forestry workers, rural firefighters), long-term suppression of the consequent chronic dermatitis may be obtained with the use of cyclosporine, mycophenolate, or azathioprine. Typically, this would be continued while the exposure risk persisted, but the risks and benefits of long-term immunosuppression would need to be considered.
Symptom relief
Antihistamines are used to relieve itching in mild-to-moderate dermatitis and may be used for their sedating properties in severe dermatitis, if symptoms disturb sleep. The newer, selective antihistamines are less useful. A cold compress may help relieve itching in mild dermatitis.
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