Poison Ivy – My Case Experience

written 6/9/24, updated 8/19/24

Summary

From contact to end, my experience with poison ivy (first time!) was both typical and atypical with both “normal” and “abnormal” lesions associated with it. I have history of skeeter syndrome and many other sensitivities so it does not come as any surprise that I would have a stronger/complex reaction than most people would. This is a chronicle with images and thoughts of my experience with the Toxicohedron family of plant’s irritating oil, urushiol.

Timeline

CONTACT: Sunday, May 26, 2024Contact – Small red dots with blackish brown smear like a burn on left underside of arm, fully asymptomatic, flat. Immediate issue are 3 bug bites

Day 1-2; Monday, May 27-28Bug Bites Worsening – 27th was Memorial Day. Pushed through work on 28th but suffered all-consuming discomfort from severely inflamed and spreading bug bites. Probable fever. By the end of the day on 28th, noticing a change in primary poison ivy lesion: growing more erythemic, raised, skin stretching like a burn, growing more sensitive to palpation

Day 3: Wednesday, May 29Manifested and Symptomatic – Absent from work. Placed on Medrol dose pack (methylprednisolone steroid), for 3 bad skeeter syndrome welts on both forearms

Day 4-8: Thursday, May 30 – June 3Bites Resolve, Poison Ivy Progresses Rapidly – As the bites diminish quickly in response to steroids, itchy, red dots and spots pop up and spread increasingly alongside tapering medication. 2 new Minor blistering Areas pop up on outside of right arm. All other lesions, while red and blistery seem normal for poison ivy. All areas weep constantly. Many bandaids

Day 9: Tuesday, June 4Severe Reaction Detected – As soon as the steroid stopped, the poison ivy was loosed and exponentially spread. Blistering is severe on primary lesion. Erythema spreads, turning deep red and increasingly bumpy. Suspect entire erythemic area will blister soon. 2 Minor Areas form large blisters overnight. Dog starts to notice inflammation. No interest before. Last Medrol pill taken night prior. Suspect repeat contact from improperly washed surfaces and clothing. Commence deep clean of bedding, blankets, car, tools, etc. Itching is unbearable and throwing hive/eczema spots all over body, especially around stomach area, that are far itchier than poison ivy lesions. Systemic.

Day 10: Wednesday, June 5Medical Help – Exactly 1 week later returned to PCP for poison ivy lesions this time, specifically the primary lesion. Doctor and assistant reel from severe Primary Lesion. Doctor thinks this is now cellulitis, too. New steroids prescribed, Prednisone tapering for 2 weeks, and 30 count cephalexin antibiotics. Went to work right after, unable to pick up medication until afterwards. By the time I left work, my left arm (Primary Lesion) was unusable. Difficult to make a fist or hold objects. Drove with one hand which was also starting to hurt from inflammation. Felt like someone had a vise on the arm tight. Worthy of note: apart from the local severe Primary Lesion infection, woke up in the morning feeling like a corner had been turned as a whole.

Day 11: Thursday, June 6Relief – Immediate response to strong steroid dose. Although blistering and erythema is worse on all lesions, everything feels better. Still itchy, still weeping, and still blistery. Able to bend and twist arm and make a fist. Still a little tight. Spirits are better as co-workers noted. Steroids don’t seem to help with hive/eczema spots which continue to crop up all over. Photo and heat sensitivity on skin very prominent

Day 12: Friday, June 7Pain and Progress – Primary Lesion’s blistered converged. During the course of the day, enter intense, searing, nerve-like pain every few hours. Started wondering if this is like shingles. After work and removal of bandages, noticed that Primary Lesion’s blistering is now a crater. Realized that intense pain is likely drainage and healing of the area

Day 13-15: Saturday, June 8 – Monday, June 10Intial Healing – Intense pain comes and goes. Noticeable on bigger of 2 Minor Lesions. Erythema has somewhat faded, though still present throughout. Blistering has noticeably stalled on all lesions. All eczema/hive lesions are crazy itchy while poison ivy lesions no longer itch or even hurt except Primary Lesion upon palpation or pressure. Many nighttime bathroom awakenings. Tapering of prednisone started. Hive/eczema lesions so itchy, starting to wonder if allergic to cephalexin. Primary Lesion begins to harden, crater and exhibit incredible, intense, sharp pains every few hours. Attributed to draining and internal healing. Most lesions’ itchiness has lowered in intensity, though hive lesions continue to pop up as prednisone tapers. Scratched a smaller hive and created bruising

Day 16-17: Tuesday, June 11-12Healing and New Hives – Growing depressed. This has been going on for a long time and starting to mentally feel unwell. Cratering has increased in Primary Lesion while blistering subsides and skin begins to peel. Minor Lesions are weeping blisters, but a hole forms in one which starts to harden and scab. No craters like Primary Lesion. “Normal” lesions fade in color and weep minorly. Right Elbow Patch starts to fade in color, still itchy. Left bicep area grows itchier and forms new patches. Belly Lesion darkens, but begins to grow in size. New problem: Upper Belly forms new red dots that are very itchy. Very photosensitive on all skin

Day 18: Thursday, June 13 Scab Cracking – Excitement! Morning shows a crack halfway through Primary Lesions’ scab. Throughout the day pieces break off. Itchy in a scab way. By the end of the day, much has fallen off, showing new skin underneath! Erythema lessens on all initial poison ivy contact lesions. Left Bicep area’s erythema increases along with itchiness. Belly Lesion noticeably grows larger and Upper Belly patches increase in size and itchiness. Sleeping is growing difficult

Day 19-21: June 14-16Continued Healing and Increased Hive Activity – All Poison Ivy Lesions continue to heal. Prednisone tapers more and finally rid of cephalexin. Primary Lesions develops redness within the new skin which is worrisome as it’s raised and shaped exactly like the initial contact lesion. Not overly symptomatic, however. Minor Lesions continue to harden and scan with minor cratering. “Normal” Lesions continue to fade in color, have not been a problem. Friday, June 14 is torture at work because I stupidly cut prednisone pill in half, afraid of not having the double dose in the day resulting in major withdrawal symptoms. Unable to stay awake longer than 30 minutes at a time. It’s obvious my body is addicted. All hive lesions continue to worsen except the first Right Elbow lesion. Sleeping is next to impossible except for a few hours at a time. Extremely itchy and uncomfortable around the belly and upper arms. Difficult to concentrate on anything. Decided to start treating hive lesions like eczema condition with heavy lotion use, and not eating anything that could remotely set off allergic reactions. Haven’t slept well in many days. Eyes feel like the desert. NEW PROBLEMS: skeeter syndrome bumps begin to inflame (they do that) and leg hive/eczema lesions flare up. Very itchy

Day 22-26: June 17-21Finished Medications and Lessening of all Lesions – Day 24 marked the first day of zero medications, and provided for another day of withdrawal symptoms, though not as bad. Sleeping growing more comfortable. Overall condition is better and able to communicate well with coworkers and patients. Every day itchiness lessens and skin peels all over. Quit having to use heavy duty skin treatments except on leg. More energy and increased desire to accomplish tasks. Less photosensitivity. Stupid skeeter syndrome bumps.

Day 27-28: June 22-23Almost Normal – Everything is better. Leg. Belly. Arms. Even skeeter syndrome bumps. Primary Lesion is healing nicely, with a little more ways to go. Minor Lesions are almost fully healed, though still peeling. Forehead has grown a hard little bump, asymptomatic. Elbow and Bicep lesions no longer itch. Belly Lesions only sometimes itch. Leg lesions are getting better. I feel better all around! 1 month mark has been met. Lesions are all sensitive to heat (heatwave right now), but significantly less photosensitive

Pictures!!

*WARNING* Images might be gross to some people

Primary Lesion – Left Forearm Underside

Day 3

Day 6

Started oral methylprednisolone on Day 3 Have treated with 3-4 rounds of Zanfel at this point. Day 6 is larger and raised but contained thanks to the steroid. Note the blistering starting on Day 3 under the dark streaking and growing on Day 6

Day 7 – 7:47 am

Day 8 – 7:36am

Last days of methylprednisolone. Started tracing the outline. Noticeably blistery and raised. Not overly hot yet. Colored rings show the progression of size

Day 9 – 6:26am

Day 9 – 6:44pm

Day 9: 12 hours apart. Growing worse! Blistering and erythema significantly worse. Last pill of tapering methylprednisolone taken night prior on Day 8. VERY uncomfortable. Starting to feel effects on finger joints, much pressure from inflammation on arm

Day 10 – 6:18am

Day 10 – 9:25pm

Doctor Day! Couldn’t come fast enough! Severe inflammation, blistering, erythema, heat, itchiness, pain. Doctor suspects possible cellulitis. Rx prednisone and cephalexin. Unfortunately, could not get medication until after work. So much pressure and inflammation that hand became unusable by the end of the day. Unable to grip objects securely. Notice the dark red coloring, almost purpling

Day 11 – 6:14am

Day 11 – 7:56am

2 views in different light. Looks terrible with much more blistering, but medication started night prior and it felt a ton better. No longer blazing hot, less redness, able to twist, bend, and grip

Day 12 – 6:21am

Day 12 – 8:25am

Blisters have converged into a large one (the whitish pink is calamine lotion that got stuck in the bumps and ridges). Right image is a good view of the skin blistering that continues to spread but much more slowly around the red areas. New symptom: crippling, sharp pain that seemed to pierce the arm’s nerves. Would come on every few hours during the day

Day 13 – 10:40am

Day 14 – 8:43am

It seems that the intense sharp pain has something to do with the cratering that has appeared. Blisters are draining and leaving behind a dark, hard…scab? Noticeable lightening of erythema between two images

Day 15 – 7:27am

Day 16

Cratering is even larger and harder. Signs of skin peeling and scab shedding. Fading blistering

Day 17

Day 18 – 6:21am

Progress! It cracked in half overnight and you can see new skin underneath!

Day 18 – 6:11pm

Day 18 – 9:19pm

Very itchy owing to scab shedding.

Day 19 – 6:16am

Day 19 – 9:49pm

Worrisome progression of the new skin. The red, raised dots on the new skin look exactly like the initial poison ivy contact. Itches to touch, but otherwise not bothersome

Day 20 – 8:42am

Day 21 – 8:05am

Looks kind of bad! However, the redness is dry, not significantly raised and appears to be peeling off slowly. No symptoms to palpation aside from minor sensitivity. VERY photosensitive!

Day 22

Day 23

Day 24

Day 26

Day 24 is the first day with no medications at all. Redness is fading and peeling, too, thank goodness!

Day 28 (1 month) – 6/23

Day 35 (5 weeks)

Significant improvement by 28-day (1 month) mark! Itchy and dry to the touch. Been applying lotion. 5-week mark shows improvement, but still there and still peeling

Day 42 (6 weeks)

Day 105 (3.5 months)

6 Weeks: Much less photosensitive, but still peeling and rough. What you can’t see is that the entire area that the lesion covered initially continues to be darker in color than the rest of the arm, almost like a port wine stain. 3.5 Months: I actually forgot about it (or blocked it out??). Rarely, it will itch likely from dryness. The skin on my arm is still darker in color than the rest of the skin, but feels smooth to the touch

Other Lesions

Aside from the Forehead one, these all cropped up as soon as the initial Medrol dose pack steroid (methylprednisolone) tapered and finished (last pill was night of Day 8). Prednisone and cephalexin administered night of Day 10

2 Minor Lesions – Right Forearm Outside

Day 7

Day 9

Day 10

Day 11

Day 12

Day 13

Day 14 (2 weeks)

Day 15

Day 16

Day 17

Day 18

Day 19

Day 20

Day 21

Day 22

Day 23

Day 24

First day with zero medications

Day 26

Day 28 (1 month)

Day 42 (6 weeks)

Day 105 (3.5 months)

By 3.5 months, I no longer remember that I had it. Scars remain and continue to heal. Completely asymptomatic. Skin will occasionally itch as it sheds and heals

Forehead Lesion – Present Since Contact

Fastest to heal

Day 9

Day 10

Day 11

Day 12

Day 13

Day 14

Day 15

Day 18

Day 21

Day 28 (1 month)

Day 42 (6 weeks)

Day 105 (3.5 months)

3.5 months: This healed the fastest by far. This far out a faint scar remains

“Normal” Lesions

This is what I assume a “normal” reaction to poison ivy would be. You can see the lines where the plants brushed up against the skin. It blistered, it wept, it was itchy, and got red, but it wasn’t excessive. Really, wasn’t all that bad.

Left Forearm Outside

Day 9

Day 10 – 6/5

Day 11

Day 12

Day 13 – 6/8

Day 14 (2 weeks)

Day 15

Day 17 – 6/12

Day 19

Day 21

Day 22

Ignore the 2 red lesions. Those are skeeter syndrome lesions

Day 23

Sorry, my camera focused on my shirt instead of my arm

Day 24

First day with no medications

Day 26

Again, the red lesions are not poison ivy

Day 28 (1 month)

Fading significantly, with a new bug bite farthest south

Day 35 (5 weeks)

Day 42 (6 weeks)

The Poison Ivy lesions have mostly healed. The 2 skeeter bites are healing (ignore those)

Day 105 (3.5 months)

3.5 Months: Scarring still present but continue to heal. Completely asymptomatic. Ignore the 2 skeeter syndrome bites which are also healing

Right Forearm Inside

Only ever minorly itchy. Did an experiment where I popped the blisters when they first came up. Don’t do that.

Ignore the red bug bite lesion
Day 21 – 6/21
Day 28 – minor peeling, zero symptoms
Day 105 (3.5 months) – Faint scarring

Hive/Eczema/Rash Lesions

These didn’t act like the poison ivy lesions. They did not produce blisters and they itched 100x worse. The doctor confirmed that it was a systemic response. The big ones got leathery. I treated them like they were eczema lesions and that approach seemed to work. Whatever you do, DO NOT scratch them as they seemed to spread to scratched areas!!! Started wondering if it’s an allergic reaction to the antibiotic…?

Arms

Right Elbow – Day 8 Symptom Start

Day 9 – 6/4/24

I made the mistake of scratching when it first popped up. It grew rapidly in response and got even itchier

Then it grew some more trailing lesions

Day 21 – 6/16
Day 28 (1 month) – only occasionally itchy

Mostly healed at this point. Can be itchy if irritated by a sleeve or bending the arm for too long a period of time

Day 42 (6 weeks) – finally starting to peel
Day 105 (3.5 months) – fully asymptomatic

Left Arm

Day 15 – 6/10

Evidence of scratching. Don’t do that

Day 17

Day 18

This is also extremely itchy and possibly a result of me scratching a small red hive. At one point it even spread onto the primary lesion

Day 19

Day 21– 6/16

Day 22

Day 23

Day 24

First day with no medications

Day 28 (1 month)

To clarify it’s 1 month since contact

Day 42 (6 weeks)

Finally peeling

Day 105 (3.5 months)

Just scarring. No symptoms

Torso – Day 10 Symptom Start

These popped up last and has been the WORST of all the lesions for discomfort/itchiness by far!!

Belly

Day 11 – 6/6/24
Day 15 – 6/10/24
Day 18 – 6/13/24
Day 21 – 6/16/24

Growing significantly larger and spreading to areas previously untouched. You can see the more red areas on the outskirts of the main patch and spreading towards my back. VERY itchy, but growing more painful/stingy too

Day 23 – last day of medications
Day 26
Day 28 – 6/23
Day 35 (5 weeks)
Day 42 (6 weeks) – Now that it’s healing well and only occasionally itchy, you can see the original patch and how big the area got
Day 105 (3.5 months) – Fully asymptomatic, just scarring which is slowly fading

Mid to Upper Belly

Day 16

Day 17 – 6/12

Day 18

Day 19

Day 20 – 6/15

Day 21

Growing noticeably worse as the steroids taper. Supremely itchy… more than the stomach patch

Day 22

Day 23 – 6/18

Day 26

Itching has mostly calmed, but still photosensitive

Day 28 (1 month)

Fading and no longer continually itchy

Day 35 (5 weeks)

Fading, but still photosensitive

Day 42 (6 weeks)

No longer itchy except on occasion

Day 105 (3.5 months)

Fully asymptomatic. Scarring is slowly fading

Leg

Day 21 – 6/16

Started popping up. Image is upside down

Day 22

Day 23

Spreading

Day 24

First day with zero medications

Day 24 – Closeup

Nasty bumpy, and extremely itchy

Day 21

Darkening = less itchy

Day 28 (1 month)

Note: 1 month since initial contact

Day 35 (5 weeks)

Starting to peel, itchy

Day 42 (6 weeks)

Still itchy, but not as much. Still peeling

Day 105 (3.5 months)

Completely asymptomatic aside from occasional itching from healing skin

Second Contact with Prompt Treatment

I got it AGAIN! On July 4, 2024. I had barrier lotion on while doing yardwork and attempting to eradicate it physically but didn’t have face protection and something brushed up against my face. Within 2 hours I had doused my face in 91% isopropyl alcohol, bathed in Dawn dish soap, and scrubbed with Zanfel. I knew it wasn’t a mosquito bite because (unlike the one on my ear) it didn’t itch right away, just started welting up and inflaming, no other symptoms. Because of the quick action, I (think so far) have been able to contain the reaction. It itches and twinges, but so far nothing else. Here are pictures!

Right Cheek

Contact – 8:45 am (2-3 hours)

8:51 am (post-Zanfel)

11:00 am

Starting to raise

Day 1 (7/5)

Day 2

More noticeable!

Day 3

Distinct bumpiness to both lesions

The others didn’t get bad until a week later, so here’s hoping it doesn’t get worse! Day 1 felt the inflammation affect ability to move cheek. The worst itchiness so far has been Day 2. Day 3 has more of an awareness so far

Day 43 (6 weeks)

Day 43: Itches a few times a day, tingling worse than usual within the last 48 hours. Suspect healing.

Recommended Treatment and Info

From Professionals

  • Homecare for most cases (mild-moderate reactions)
  • Severe cases (i.e. difficulty breathing or swallowing, facial swellings where eyes shut, worsening itchiness, full body rash, fevers) require IMMEDIATE medical attention
  • If/when you come in contact with the plants, as soon as possible, clean the affected areas with soap (even laundry detergent) and warm water. You can also use rubbing alcohol or OTC poison ivy washes. The faster you get it off, the less chance there is of strong reaction
  • Wash ALL affected clothing and gear including shoelaces in the laundry thoroughly in longer cycles. It is recommended to wear gloves to prevent the spread as you remove your clothing.
  • Use OTC products such as poison ivy washes, calamine lotion, topical antihistamines, oral antihistamines, cool compresses to relieve itchiness
  • Do NOT scratch and leave blisters alone to prevent infection
  • Most rashes take anywhere from 2-3 weeks to clear up on their own and can seem to get worse before getting better. Reaches peak outbreak around 2 weeks

First exposures take longer to produce lesions as the body is slower to sensitize. Subsequent exposures appear much more quickly and last for the rest of your life.

Lesions are not contagious and liquid from popped blisters will not spread the rash because the liquid is just the body’s fluid, not more urushiol oil.

Useful Treatments

Zanfel

Tecnu

Domeboro

Calamine Lotion

Cortisone

Eucerin Lotion

Antihistamines

UV Sleeves

Bandaids

Poison Ivy, Poison Oak, Poison Sumac

written 6/1/2024, updated 6/17/2024

Family Anacardiaceae

The Cashew/Sumac Family: Deciduous trees and shrubs that produce an oily or milky sap that can be highly poisonous. Resin canals that exist in stems, leaves, and roots are found in all plants in the family. Their fruits are called drupes (stone fruit) where the fleshy part of the fruit surrounds a single shell which houses a seed

Common Plants: Anacardium occidentale (Cashew); Mangifera indica (Mango); Pistacia vera (Pistachio); gen Cotinus (Smoke Tree); gen Rhus (Sumac); gen Toxicodendron (Lacquer Tree, Poison Ivy, Poison Oak, Poison Sumac)

Note: The Toxicodendron genus used to be lumped under Rhus. Toxico – dendron means toxic – tree.

Poison Ivy (Toxicodendron Radicans)

Native to most of the USA and southern Canada, it can be found in many types of environments from wet to dry, woodlands, valleys, clearings, roadsides, and backyards. Poison ivy can exist as either a shrub (trailing, erect, or bushy) or a woody climbing vine with aerial roots. It exhibits woody underground rhizomes. All aspects of the plant are poisonous, containing the persistent oily irritant, urushiol. It is said that the vine version can cause 10-100 worse symptoms than the shrub variety

Size: 6 ft shrub or 62-150 ft climbing vine

Location: Various areas from wet to dry, woodland to ditches to backyards

Uses: Food and shelter to animals, birds, and insects

Identification: Leaflets of 3 where the middle leaflet is longer than the other 2. Leaves can be smooth, serrated, or lobed. It has gray, reddish stems, and glossy green leaves that turn vibrant reddish yellow in autumn.

Flowers and Fruit: Flowers are many and clustered; Fruit look like waxy, greenish-white berries

Control: Do NOT burn. Fully cover the skin, protect face and eyes, wear a hat. Remove any gear and clothing that come into contact with the plant. Cut and remove roots of plant. Do NOT put in compost pile. Rather, place in trash bag. Use of herbicides on exposed roots/stumps.

Note how the middle leaf is set out longer than the other 2 leaves. This is characteristic of Poison Ivy

Here you can see the Poison Ivy interspersed amongst other plants and vines. The red are Poison Ivy, the purple is English Ivy, and the blue are Virginia Creeper

There’s a massive Poison Ivy problem at this house. Can you spot it amongst all the other plants here?

The vine variety

Poison Oak (Toxicodendron pubescens)

Source same as below

Low-growing shrub native to Central and Eastern USA, it is found in dry, sandy locations in woodlands and thickets. The word pubescens is latin for “covered in hair,” and the plant is named such owing to the fine hairs on stems and leaves. The plant roots are rhizomes and often form dense colonies. Yellowish-green flowers appear in the springtime, resulting in green-tannish white drupes (fruit) by late spring. All aspects of the plant are poisonous, containing the persistent oily irritant, urushiol.

Size: 2-4 ft shrub on average, can be as tall as 10ft

Location: Prefer dry, sunny areas. Woodlands, thickets.

Uses: Food and shelter to animals, birds, and insects

Identification: Alternating green, lobed leaflets of 3 that crowd towards the end of the stem. The leaves look similar to Oak tree leaves. Often, the middle leaf is fully lobed while the other 2 are irregularly lobed. Fine hairs cover the both the undersides and upper parts of leaves as well as the stems. Tend to grow in clumping colonies. Leaves turn vibrant reddish yellow in autumn.

Flowers and Fruit: Flowers are hanging yellow-green panicles (like rice or oats), and fruit are clusters of hairy green or tannish-white drupes that appear waxy

Control: Do NOT burn. Fully cover the skin, protect face and eyes, wear a hat. Remove any gear and clothing that come into contact with the plant. Cut and remove roots of plant. Do NOT put in compost pile. Rather, place in trash bag. Use of herbicides on exposed roots/stumps.

SOURCE. You can see how they grow in clumps. Notice how the 2 leaves are more irregularly lobed than the middle leaf which, like poison ivy is set out a little

Poison Sumac (Toxicodendron vernix)

Deciduous small tree or shrub, it is native to eastern and central-eastern USA, and eastern Canada. There are many look-alike plants. Typically, Poison Sumac will not grow in clumps and since it prefers wet areas, will not be found in dry locations, nor will it be commonly found along roadsides and fields. While it is the least likely of the big 3 to be exposed to, effects of the urushiol from Poison Sumac tend to be more severe than its Poison Oak and Ivy relatives.

Size: 5-25 ft tree with sparse, open form, or erect shrub

Location: Prefer marshy, boggy, wet locations like riverside thickets, acidic soil, and full to part sun

Uses: Food and shelter to animals, birds, and insects

Identification: Long, smooth, paired leaflets of 7-13, with a single leaflet at the end. Stems are reddish, bark is smooth, gray-brown in color, and contain lenticels (small holes or lines on trunks that facilitate gas exchange). Leaves turn reddish yellow in the autumn. Black sap

Flowers and Fruit: Greenish-yellow, 5-petal flowers hanging in panicles (think rice and oats). Fruits are yellowish-white drupes that hang loosely downwards in clusters

Control: Do NOT burn. Fully cover the skin, protect face and eyes, wear a hat. Remove any gear and clothing that come into contact with the plant. Cut and remove roots of plant. Do NOT put in compost pile. Rather, place in trash bag. Use of herbicides on exposed roots/stumps.

SOURCE

Reddish stem, leaflets ending in a single leaflet, grayish brown bark

Urushiol

Urushiol is an oleoresin (oil + resin) found in the sap of plants in the family Anacardiaceae. It has potent allergenic properties that affect most humans on contact, causing urushiol-induced contact dermatitis. The chemical is persistent and can last for months on clothing and gear unless cleaned thoroughly with soap + water or rubbing alcohol.

Its irritating effects are only applicable to humans and a few primates. Other animals like dogs, cats, deer, birds, etc. are not affected. In fact, birds, deer, cattle, goats, and other wildlife benefit and feed from the plants.

Sciency Stuff

ChemSpider 2D Image | Urushiol I | C21H36O2

Molecular Formula: C21H36O2

Molecular Weight: 1584.4 g/mol

Average Mass: 320.509 Da

Monoisotopic Mass: 320.271515 Da

Source & Source

Toxicohedron Control – Before and After

Vinegar Solution

Pros: Natural ingredients, no harsh chemicals

Cons: Strong vinegar smell, easily washed off with water/rain, must use strong enough vinegar concentration, for best results use when sunny and hot, not substantive and needs reapplication

Regular white vinegar is only 5% acetic acid (and 95% water). You’re definitely going to want a higher concentration for this which can be found easily in hardware stores up to 30% (usually in the cleaning and/or garden sections), but you can get them even higher online. I ended up buying the 45% concentrated solution (there’s even 75% or 95%). The general formula is:

1 gallon Vinegar (read the label on the concentrated ones for dilution ratio)

1 Tbsp Dishsoap

1 cup Salt

Get yourself a nice pump sprayer like the one I use (can be any brand, I just happened to have this)

You can also buy pre-mixed weed killer solutions like this one that I tried for regular weeds. Notice that it’s 20% vinegar which I found to be good for most weeds, but not enough for some tougher ones like crab grass.

Results of Vinegar

1 week apart

2nd treatment

3rd treatment

RoundUp and similar products

Pros: Strong, substantive, 30-minute rain ready

Cons: Environmental persistence and downstream effects, possible health implications

I really dislike using RoundUp, but I really don’t want to mess with Poison Ivy especially given my terrible reaction to it. Ever since the issue with glycophosphates and cancer, RoundUp has changed their formulations away from glycophosphates. Also, RoundUp doesn’t care if it rains (30 minute rain ready) or if it’s sunny outside. It’s likely more substantive than vinegar, too. Just make sure you use eye protection and a mask

Active ingredients:

Triclopyr, triethylamine salt (0.122%)selective herbicide for broadleaf and woody plants

Fluazifop-P-butyl (0.097%)selective post-emergent herbicide

Diquat dibromide (0.073%)non-selective algicide defoliant, dessicant, and herbicide

I chose the RoundUp specifically for poison ivy. The built-in wand is rather subpar. If you have one, it’s better to dump it into a pump sprayer and do it that way

Results of RoundUp

I was initially SHOCKED by how poorly RoundUp did, but now, looking at the image compare, I guess it did kind of work on specific plants. Didn’t even touch the English Ivy, but you can see wilting and drying of the actual poison ivy. Unfortunately, they’re still there, just wilted, so perhaps more treatments are in order.

Before

After

I drenched the holy heck out of this plant with the RoundUp. It did not work as well as I thought it would

Fun Facts

The name urushiol comes from the Japanese name for the lacquer tree, urushi.

In 2016 an international group of scientists discovered that a molecule found abundantly in human skin, CD1a, is responsible for the reaction of humans to urushiol contact. CD1a is expressed by Langerhans cells in the skin. Langerhans cells are part of the immune system, and the CD1a molecule it produces acts by presenting lipid antigens to T-cells. Since urushiol is an oleoresin, the now activated T-cell releases cytokines, causing both inflammation and itchiness. Interleukin-33 was isolated as a key cytokine in mouse studies, along with its receptor ST2 on the small to medium dorsal root ganglion neurons. By blocking the interleukin-33/ST2 (IL-33/ST2) signaling pathway, relief from the horrible itchiness of urushiol can be attained. Interestingly, IL-33 is also associated with eczema/atopic dermatitis and asthma. With this information, a vaccine is currently in the works to help desensitize the body to urushiol’s potent irritating effects.

Urushiol is found in some members of the Anacardiaceae family including poison ivy, oak, and sumac, as well as mango skins, cashews, and pistachios

Sources