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) — 623

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 1065

Day 11

Day 12

Day 1368

Day 14 (2 weeks)

Day 15

Day 17612

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 — 621
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 — 616
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 15610

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- 616

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 — 623
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 — 612

Day 18

Day 19

Day 20615

Day 21

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

Day 22

Day 23618

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 21616

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