From the Guidelines
Oral prednisone and antihistamines are effective treatments for poison sumac rash, with oral prednisone (typically 0.5 – 1 mg/kg/day) and antihistamines (e.g., cetirizine/loratidine 10 mg daily) being recommended for intense or widespread reactions 1. For severe poison sumac reactions, this combination can significantly reduce inflammation and itching.
- Common antihistamines include diphenhydramine (Benadryl) 25-50mg every 6 hours or cetirizine (Zyrtec) 10mg daily to help control itching.
- The combination works well because prednisone suppresses the immune response causing the rash, while antihistamines block histamine receptors that trigger itching.
- Cool compresses, calamine lotion, and avoiding scratching can provide additional relief.
- If the rash covers large areas of your body, affects your face or genitals, shows signs of infection (increasing pain, pus, swelling), or if you experience difficulty breathing, seek immediate medical attention.
- Thoroughly wash all clothing and items that may have contacted the plant to prevent re-exposure, as recommended by the 2024 American Heart Association and American Red Cross guidelines for first aid 1. It's essential to start treatment as soon as possible after exposure for best results, considering that contact dermatitis from Toxicodendron species can affect millions of Americans annually, resulting in significant morbidity 1.
From the Research
Treatment Options for Poison Sumac Rash
- Oral prednisone and antihistamines are commonly used to treat poison sumac rash, as well as other forms of allergic contact dermatitis caused by poison ivy, oak, and sumac 2, 3, 4.
- The duration of oral prednisone treatment can vary, with some studies suggesting that a longer course of treatment (14-21 days) may be more effective in reducing the risk of return visits and excess medication use 3, 5.
- Antihistamines can provide symptomatic relief, such as reducing pruritus and urticaria, and are often used in conjunction with oral prednisone and topical corticosteroids 4.
- Topical corticosteroids are also used to treat localized non-facial eruptions, while systemic corticosteroids are reserved for more severe cases 4.
Considerations for Treatment
- The severity of the reaction and the presence of systemic involvement can impact treatment decisions, with more severe cases requiring physician consultation and potentially longer courses of treatment 2, 5.
- Patient education on preventive measures, such as avoiding contact with the plants and washing exposed skin within 2 hours, is also an important aspect of treatment 2, 4.
- Healthcare utilization outcomes can be impacted by prescription practices, with shorter duration oral corticosteroids and initial treatment at the ED associated with increased risk of return visits 5.