Poison ivy rash is caused by an allergic reaction to an oily resin called urushiol found in the leaves, stems and roots of poison ivy, poison oak and poison sumac plants. For most people, the rash normally goes away within 1-3 weeks after exposure. However, in some cases the rash and itch can persist for longer. There are several reasons why poison ivy may still be spreading or getting worse more than a week after initial exposure.
You’re still being exposed
The most common reason poison ivy continues to spread is that you’re still coming into contact with the plant and urushiol oil, either by touching infected areas on your skin and then touching other areas, or by direct contact with the plant again. Urushiol oil can stay active on virtually any surface like clothes, shoes, tools, pets etc for weeks after exposure. So if you haven’t thoroughly washed everything that may have touched the plant, you may be continuing to spread the oil and cause new rash. Carefully check your home, yard, car and workplaces for any remaining poison ivy plants and thoroughly scrub any objects that may have been exposed.
You’ve developed a bacterial infection
The open, weeping blisters caused by severe poison ivy rash are prone to bacterial infection. Scratching can further damage the skin and allow bacteria to penetrate. Signs of a bacterial infection include oozing pus, increasing pain, swelling and redness beyond the original rash. See a doctor if you suspect an infection, as oral antibiotic medication may be necessary to clear it up. Keeping the skin clean and avoiding scratching is key.
You have spread the rash
Even after the original poison ivy exposure, the rash can be spread to other parts of the body by touching or scratching the blisters and then touching elsewhere. The fluid inside the blisters still contains urushiol oil. Avoid bursting blisters and thoroughly wash hands after contact to prevent spreading. Keep nails trimmed to minimize damage from scratching.
You’ve had a severe reaction
Most poison ivy rashes resolve within a few weeks, but some people have an immune system that overreacts severely to urushiol, leading to an intense, prolonged rash. People who are highly sensitive can outbreak again after the initial rash starts fading. The plant oil can remain under the skin surface for months, causing recurrent activation of the immune response. See a dermatologist if rash and itching persists longer than 3-4 weeks.
You have been re-exposed to urushiol oil
Even after poison ivy rash has cleared up, people remain sensitized to urushiol for a long time. Coming into contact with tiny traces of the oil again on contaminated objects or plants can cause another outbreak. Urushiol oil can stick to virtually anything and remain potent for months. Be vigilant about washing any objects that may have been exposed initially.
The rash has spread to new areas
Through scratching or touching, poison ivy rash can sometimes spread to areas like the face, arms and legs that were not directly exposed initially. The fluid from blisters contains residual urushiol that can cause new rash if spread. Avoid bursting blisters and be careful not to touch oozing areas and then touch unexposed skin. Use gloves when applying creams and thoroughly wash hands after.
You have a skin condition
People with certain skin conditions like eczema or psoriasis may be more prone to severe, persistent poison ivy rash. The damaged skin barrier allows urushiol to penetrate deeper. Underlying inflammation can also intensify the reaction. See a dermatologist for treatment if rash remains severe after 2-3 weeks.
You have a weak immune system
Those with weakened immune systems from illnesses or medications like chemotherapy may be less able to stop the spread of poison ivy rash. Urushiol oil can penetrate deeper into the skin layers. Seek medical attention if the rash continues progressing after the first week.
How to stop the spread of poison ivy rash
If your poison ivy rash seems to be getting worse or spreading instead of getting better after a week, then take action to prevent further progression and allow healing:
Identify and eliminate the source
Carefully inspect your home, yard and work area to find and remove any remaining poison ivy plants. Dig up roots and stems completely and dispose of in sealed bags. Scrub any tools, equipment or objects exposed to the plants with rubbing alcohol or soap and hot water. Wash clothing on hot cycle. Continue searching for possible sources of re-exposure. Urushiol oil can linger on virtually anything for long periods.
Clean the rash
Gently wash rash areas at least twice a day using soap and cool water to remove any lingering urushiol. Avoid very hot water which can intensify the rash. Be extremely gentle when washing to avoid damaging blisters which can spread the oil. Pat dry with a clean towel and allow skin to air dry.
Apply cold compresses
Holding a cold, wet cloth against the rash can help soothe itching and inflammation. Make compresses using cool water, not icy cold to avoid damaging skin. Apply for 15-20 minutes several times a day, especially after washing. The cold helps constrict blood vessels to reduce swelling, oozing and spread of the rash.
Use topical steroid cream
Apply an over-the-counter hydrocortisone cream containing 1% hydrocortisone 2-3 times daily. This can help reduce inflammation, itching and rash progression. Apply after washing and drying the affected area. Make sure to thoroughly wash hands after application. See a doctor if the rash doesn’t start improving within a few days of using the steroid cream or if it continues worsening.
Take antihistamines
Oral antihistamines like diphenhydramine (Benadryl) or cetirizine (Zyrtec) can help relieve the itching and swelling of poison ivy rash. Antihistamines block the histamine chemicals released by the immune system in response to the urushiol allergen. Take according to label directions. Drowsiness is a common side effect.
Apply moisturizer
Gently applying a fragrance-free moisturizer to the rash can help soothe irritation and prevent cracking which can lead to infection and spread. Avoid moisturizers containing irritants like alcohol. Apply a thin layer 2-3 times daily after washing and drying.
Take cool baths
Soaking in a lukewarm oatmeal or baking soda bath can help dry out oozing blisters and soothe itching. Avoid hot water which can worsen rash. Rinse off completely after bathing and pat dry. Apply moisturizer after bathing while skin is still slightly damp.
Cover the rash
Lightly covering the affected areas with gauze or soft cotton may prevent scratching and spread. Change dressings at least once daily or if soaked through. Avoid adhesive bandages which can further irritate skin. Discard used dressings immediately.
Try wet wraps
Wet wrap treatment involves first applying topical steroids, then wrapping the area with cool, wet bandages covered by a dry outer layer. This can help draw out oozing and urushiol, reduce itching and speed healing. Do not attempt wet wraps without guidance from a doctor.
Get medical treatment
See a doctor right away if the rash worsens or doesn’t start improving within a few days of self-treatment, or if you develop signs of infection like oozing pus, increased swelling, redness and pain. You may need oral steroid medication or other prescription remedies to stop progression and help heal the rash.
Prevent scratching
Scratching poison ivy rash can greatly worsen and spread it by further damaging the skin and releasing fluid containing urushiol. Trim fingernails short. Apply cold compresses when itchy. Distract yourself with activities. Have someone apply anti-itch creams for you. Wear cotton gloves at night.
Watch for signs of infection
Look out for increasing redness, swelling, pain, warmth at the rash site and any oozing yellow or green fluid, which indicates a bacterial infection setting in. See a doctor promptly for antibiotics if these symptoms develop to prevent the infection from becoming serious.
When to seek emergency medical attention
Most poison ivy rash improves with self-care, but emergency care is needed if:
– Rash develops on face or genitals
– You have trouble breathing or swallowing
– You develop a high fever over 101 F
– Rash is widespread and intense
– Infection causes streaking redness from rash
– You have a known allergy to poison ivy
Long term outlook and prevention
With appropriate treatment and avoidance of further exposure, most poison ivy rash resolves within 1-3 weeks without permanent effects. However, in some people severe rash can last for months. About 15-30% of people have recurrent outbreaks due to high sensitivity to urushiol oil. Prevent future poison ivy rash by learning how to identify the plants, wearing protective clothing when outdoors, and avoiding contact with contaminated objects. See an allergist about allergy testing and potential desensitization if you have frequent or severe poison ivy reactions.
Conclusion
Poison ivy rash and itching can persist longer than normal if you have an intense allergy reaction, get re-exposed to the urushiol oil, infect the rash by scratching, or fail to eliminate the plant from your environment. Promptly treat rash outbreaks by washing with soap and water, using cold compresses, topical steroids and antihistamines. Avoid scratching and contact with oozing blisters. Seek emergency medical attention if rash spreads rapidly or you develop signs of severe infection. Identify and remove any remaining poison ivy plants and be vigilant about washing contaminated objects to prevent ongoing exposure and recurrence of rash. Most rashes do resolve within several weeks with proper treatment and prevention.
| Cause | Signs | Treatment |
|---|---|---|
| Continued exposure to plant | Rash spreading to new areas, recurrent outbreaks after initial improvement | Eliminate any remaining poison ivy plants, wash contaminated objects and clothing |
| Bacterial infection | Increasing pain, swelling, redness, oozing pus, streaking redness from rash | See a doctor promptly for oral antibiotic medication |
| Scratching and spreading rash | Rash developing in areas not directly exposed, fluid-filled blisters | Trim fingernails, gently wash rash, apply cold compress |
| Severe allergic reaction | Very intense, widespread rash, recurring outbreaks | See a dermatologist for treatment options |