What is the treatment for Toxicodendron vernix (poison sumac) rash?

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Last updated: May 7, 2025View editorial policy

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From the Guidelines

Poison sumac rash should be treated by washing the exposed area with soap and water as soon as possible after exposure, as this can remove up to 100% of the poison ivy oils if done immediately. This is based on the most recent guidelines from the American Heart Association and American Red Cross [ 1 ]. The effectiveness of washing with soap and water decreases over time, with a 50% reduction in effectiveness at 10 minutes, 25% at 15 minutes, and 10% at 30 minutes [ 1 ].

Treatment Options

  • Washing with soap and water or a commercially available decontamination product is recommended as soon as exposure to poison sumac is recognized [ 1 ].
  • The usefulness of over-the-counter topical steroids, such as hydrocortisone cream, to alleviate local symptoms from poison sumac is uncertain [ 1 ].
  • Cool compresses may be considered for relief of local symptoms from exposure to poison sumac [ 1 ].
  • Oatmeal baths may be considered for relief of local symptoms from exposure to poison sumac [ 1 ].
  • The usefulness of over-the-counter antihistamines to alleviate local symptoms from poison sumac is uncertain [ 1 ].

Severe Cases

For severe cases of poison sumac rash, covering more than 10% of the body, affecting the face or genitals, or accompanied by fever, seek medical attention as prescription-strength steroids may be necessary. The rash typically resolves within 1-3 weeks. Poison sumac causes this allergic contact dermatitis through urushiol oil, which triggers an immune response in about 85% of people [ 1 ].

Prevention

Avoid scratching the rash to prevent infection. The resulting rash appears as red, swollen skin with blisters that may ooze clear fluid before crusting over during healing. Washing with soap and water as soon as possible after exposure is the most effective way to prevent the rash from developing [ 1 ].

From the FDA Drug Label

Uses temporarily relieves itching associated with minor skin irritations, inflammation, and rashes due to: ... poison ivy, oak, sumac ...

  • Hydrocortisone (TOP) can be used to temporarily relieve itching associated with poison sumac rash.
  • It is intended for minor skin irritations and rashes, and its use for other purposes should be under the advice and supervision of a doctor 2.

From the Research

Poison Sumac Rash Overview

  • Poison sumac rash is a type of allergic contact dermatitis caused by exposure to urushiol, an oil found in poison sumac, poison ivy, and poison oak plants 3, 4.
  • The rash typically presents as a pruritic erythematous rash with vesicles and bullae in areas that were in contact with the plant 3.

Symptoms and Treatment

  • Symptoms of poison sumac rash usually appear 24 to 48 hours after exposure and can be managed with various treatments, depending on severity 3.
  • Treatment options include washing the affected area with a solvent, using anti-inflammatory agents such as corticosteroids, and applying cold compresses 5, 6.
  • Topical corticosteroids are commonly used for localized non-facial eruptions, while systemic corticosteroids are used for severe eruptions 6.

Prevention

  • Avoidance is the primary way to prevent poison sumac rash, highlighting the importance of educating patients on plant identification 3, 7.
  • Prophylactic measures include wearing protective clothing, applying barrier creams, and washing exposed skin within 2 hours of contact 5, 6.
  • Approximately 50% to 75% of the US adult population is clinically sensitive to poison ivy, oak, and sumac, making prevention crucial 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Poison Ivy, Oak, and Sumac Dermatitis: What Is Known and What Is New?

Dermatitis : contact, atopic, occupational, drug, 2019

Research

Toxicodendron Contact Dermatitis: A Case Report and Brief Review.

The Journal of clinical and aesthetic dermatology, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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