Signs and symptoms of a poison ivy rash include:

• Redness
• Itching
• Swelling
• Blisters
• Difficulty breathing, if you’ve inhaled the smoke from burning poison ivy

A poison ivy rash will often appear in a straight line because of the way the plant brushes against your skin. However, if you develop a rash after touching a piece of clothing or pet fur that has the poison ivy oily resin on it, the rash may be a little more spread out. You can also transfer the oil to other parts of your body with your fingers. The reaction usually develops 12 to 48 hours after exposure and can last up to two to three weeks.

Poison ivy, poison oak, and poison sumac all produce similar rashes, and so can be treated as such.

Don’t scratch the blisters. Bacteria from under your fingernails can get into them and cause an infection. The rash, blisters, and itch normally disappear in several weeks without any treatment.

You can relieve the itch by:

• Using wet compress or soaking in cool water
• Applying over-the-counter skin protectants, such as zinc acetate, zinc carbonate, zinc oxide, and calamine, dry the oozing and weeping of poison ivy, poison oak, and poison sumac. Protectants such as baking soda or colloidal oatmeal relieve minor irritation and itching. Aluminum acetate is an astringent lotion that relieves rash.

A poison ivy rash is caused by an allergic reaction to an oily resin called urushiol. This oily resin is in the leaves, stems, and roots of poison ivy, poison oak, and poison sumac. It’s very sticky, so it attaches easily to your skin, clothing, tools, equipment, and pet’s fur. You can get a poison ivy reaction from:

• Touching the plant: if you touch the leaves, stem, roots or berries of the plant, you may have a reaction.
• Touching contaminated objects: If you walk through some poison ivy and then later touch your shoes, you might get urushiol on your hands. You might then transfer it to your face or body by touching or rubbing. If the contaminated object isn’t cleaned, the urushiol on it can still cause a skin reaction years later.
• Inhaling smoke from burning plants: Even the smoke from burning poison ivy, poison oak and poison sumac can irritate or harm your nasal passages or lungs.

Pus that oozes from blisters doesn’t contain urushiol and won’t spread the rash. But it’s possible to get poison ivy rash from someone if you touch plant resin that’s still on the person or contaminated clothing.

The best way to avoid getting a reaction is to avoid the plants altogether. Learn how to identify poison ivy, poison oak, and poison sumac in all seasons, and if possible, remove or kill the plants. When hiking or engaging in other activities that might expose you to these plants, try to stay on cleared pathways. Wear socks, pants and long sleeves when outdoors. If camping, make sure you pitch your tent in an area free of these plants.

You should also wash your skin or your pet’s fur. Within 30 minutes of exposure to urushiol, use soap and water to gently wash off the harmful resin from your skin. Also clean contaminated objects, such as clothes, that may have come in contact with the oil. Handle contaminated clothing carefully so that you don’t transfer the urushiol to yourself, furniture, rugs or appliances.