In the United States, poison oak, poison ivy, and poison sumac are some of the leading causes of rashes. The rash is an allergic contact dermatitis triggered by an irritant oil from the plant. It occurs after contact with the plant itself, with clothing or pets with recent plant contact, or even with the smoke of burning plants. The rash usually develops one to two days after exposure and is characterized by redness, swelling, blisters, and itching. Allergic contact dermatitis rashes are not contagious, nor can you spread the rash to others by contact with you (assuming you’ve washed off the irritant oil with soap and water), even the fluid in your blisters. The rash appears at different times on different parts of your body because your skin reacts first in areas that had the most oil on them. These rashes usually take 3-4 weeks to resolve completely.
- Familiarize yourself with the appearance of poison oak, poison ivy, and poison sumac plants, especially those most common in your region.
- Remove all clothing if you have had contact with these plants. As soon as practical after exposure, wash your skin well with soap and warm water to remove the irritant oil. Launder the clothing promptly.
- Apply calamine lotion or an over-the-counter hydrocortisone cream to soothe skin
- Take a lukewarm bath and try an over-the-counter antihistamine, such as Benadryl®, to relieve itching. Antihistamines may help with the symptom of itching, but have no direct effect on this type of allergic reaction.
- Try to avoid scratching the rash. Keep your fingernails clean to help prevent secondary bacterial skin infections.
Seek medical attention if:
- The rash is present on the face, mouth, eyes, or genitals, or involves a large body area
- The rash is causing undue intrusion into your daily life, especially if it is impeding sleep
- You develop worsened inflammation, pain, or other signs of a secondary bacterial infection of the skin (cellulitis)