Poison Ivy Rash: How Long It Lasts, What Helps, and When to Get Seen
Poison ivy grows along Colorado's foothill trails and creeks. How the rash spreads, how long it lasts, what helps the itch, and when to see a clinician.
A poison ivy rash is an itchy, red, often blistering reaction to an oil in the plant, and it usually appears a day or two after contact and lasts one to three weeks. Most cases can be handled at home with cool compresses and anti-itch care. See a clinician if the rash is on your face, eyes or genitals, covers a large area, or shows signs of infection.
Poison ivy in Colorado
Western poison ivy grows across the Front Range, often along creeks, ditches and trail edges in the foothills. It can be a low plant or a small shrub, with clusters of three leaflets that are shiny green in summer and turn red or orange in the fall. "Leaves of three, let it be" is still a good rule. The plant can cause a rash in any season, including when the leaves are gone.
What causes the rash?
The rash is an allergic reaction to urushiol, an oil in the leaves, stems and roots. Most people react to it. The oil sticks to skin, clothing, gear, tools and pets' fur, and it can stay active on them for a long time. That's how people get a rash without remembering touching the plant.
Poison ivy rash symptoms
- Intense itching
- Red patches or streaks, often in lines where the plant brushed the skin
- Bumps and blisters, which may ooze
- Swelling
The rash usually appears 12 to 72 hours after contact. It can seem to spread over several days, but that's usually areas that got less oil reacting later, or oil still on clothes or gear. The fluid in the blisters doesn't spread the rash, and the rash isn't contagious from person to person.
What to do right after contact
- Wash your skin with soap and cool water as soon as you can; the sooner, the better.
- Scrub under your fingernails.
- Wash the clothes you were wearing separately, and wipe down boots, tools and gear.
- Bathe pets that ran through the brush, wearing gloves.
How to treat poison ivy at home
- Cool compresses or cool showers
- Calamine lotion or an oatmeal bath to soothe the itch
- Over-the-counter hydrocortisone cream for small, mild patches
- Oral antihistamines, which can help some people sleep through the itch
- Keeping nails short and not scratching, which can break the skin and let bacteria in
Leave blisters alone; if they break, keep the area clean and covered. Never burn poison ivy to get rid of it. Smoke from burning plants carries the oil and can cause a serious reaction in the lungs and eyes.
How long does poison ivy last?
Most rashes peak within the first week and fade over one to three weeks. Someone who has reacted strongly before may react strongly again.
When to see a clinician
Get seen if:
- The rash is on your face, near your eyes, on your lips or genitals
- It covers a large part of your body or has many large blisters
- The itch keeps you from sleeping or isn't improving after a week of home care
- You see signs of infection: spreading redness, warmth, pus, honey-colored crusts or fever
A clinician can confirm it's poison ivy and not another kind of rash, and talk with you about prescription treatments such as a stronger steroid cream or oral medicine. Rashes are often a good fit for telehealth: a video visit with an AfterOurs clinician is $75 self-pay, available 8 AM to 11 PM daily, and the clinician will tell you if you need to come in. In the clinic, a standard self-pay visit is $175, and a self-pay in-clinic visit never costs more than $330. We contract with all major commercial and government plans, including Colorado Medicaid and Medicare. We can't guarantee a particular commercial plan has us in network; if it's out of network or denies the visit, we drop you to the self-pay rates. More on our rashes, hives and poison ivy page and the cost and insurance page.
Call 911 or go to the ER if you have trouble breathing or swallowing, swelling of the face, lips, tongue or throat, an eye swollen shut, or blistering over large areas of the body. Get emergency care too if you breathed in smoke from burning poison ivy and have trouble breathing.
Where to find us
Four clinics across metro Denver, all ages welcome, se habla español:
- Hampden (Southeast Denver): 8 AM–11 PM daily
- Littleton: 8 AM–11 PM daily
- Thornton: 8 AM–11 PM daily
- Highlands: Mon–Fri 5–11 PM, Sat–Sun 8 AM–11 PM
Walk in, or book online.
Medically reviewed by Peter Martinuzzi, MD
This article is general health information, not medical advice for your situation. If you are worried, come in or book a telehealth visit — and if it is an emergency, call 911.