Tuesday, July 1, 2014

Addendum: Allergic Reactions Associated with Agave and other Plants

Agave americana

Fellow bushcrafter, Tom Davenport, wrote me to describe a nasty allergic reaction he had while making cordage with agave.  Tom wrote: “Be advised that some species of agave have toxins in the pulp that can cause a nasty batch of contact dermatitis.”  Tom went on to say that when he was preparing a piece of agave some of the pulp landed on his exposed arms, legs and face.  The reaction wasn’t immediate but after a while he began feeling a “burning itch.”  Tom said, “[The itch] was the kind that fogs your mind.”  Tom added that the irritation was so severe that parts of his skin became blistered.

Agave neomexicana

Agave species range across the Southwest and Western states from Texas to California but can also be found in Louisiana and Florida.  Keep in mind that not all people experience reactions to agave.  These types of contact dermatitis also vary in intensity among individuals.  In other words, one person might have a severe reaction while someone else has only a mild reaction and still others have no reaction at all.  I’ve never had any sort of incident with agave even after handling it for decades but please allow me to inject an anecdote into this conversation.  Years ago I came across an interesting “weed” floating in the waters of the Laguna Madre along the South Texas coast.  I picked up this weed and examined it then handed it to my professor who held it for about two seconds then quickly handed it to another student.  The student gave the weed back to me and both she and the professor asked, “Doesn’t that burn you?”  No, it did not burn me but as it turned out I was holding a species of stinging coral.  A few years ago, however, I was making a couple of knife handles using Texas ebony and though I was wearing a dust mask I must have somehow ingested some of the wood dust.  Within a few minutes I had broken out in hives along my trunk.  My point is that we all have what’s called a biophysiological individuality—just like some people have serious allergies to peanut butter or tomatoes or kiwi fruit.  The list is long but the toxins come basically from these chemical groups—calcium oxalate, bromelain, isothiocyanates, diterpene esters, protoanemonin, and alkaloids.

The moral of this story is that we should always be careful when dealing with plants.  Remember that plants have evolved methods to dissuade predators from eating them.  Chile del monte, jalapeƱos and serrano didn’t acquire their spicy hot taste to suit your palate.  Stinging nettles sting to dissuade critters that might want to eat them.  Just like spines on cactus and thorns on shrubs and trees, plants adopted those protective methods that were selected for over millions of years. 

The best advice I can give is to be careful and carry items with you as first aid in case you have a reaction to some plant.  Here’s a prudent list of items you should carry in your pack or vehicle when on extended forays into the wilds.
EpiPen—a quick injectable dose of epinephrine. Ask your doctor for a prescription.
Benadryl antihistamine
Topical cortisone cream
In addition carry the following:
Triple Antibiotic Cream
Antibacterial lotion
A good set of tweezers. Don’t scrimp here.  Buy the best with a fine pointed end.
Bandages, various sizes
Razor blades

Sunscreen 70 SPF or greater


  1. Thanks for this information! Four days ago I brushed against an Agave plant in my brother's garden in Brisbane, Queensland, and, although not especially troublesome on the day, the irritation has worsened with time. The red burning rash covers an area about five inches by four inches on my hip (I was wearing shorts at the time and the contact was made through the material). Your description of your friend's mind "fog" equates with my own experience. I feel sick, lethargic and tired (not helped by taking an allergy tablet)and the reaction on my skin has not lessened at all. If anything, it's worsening! Now that I realise I have contact dermatitis I will use a different remedy (I happen to have a bottle of betamethasone valerate in my medical kit - I'm an allergic person!) Thanks again.

    1. Sorry it's taken me so long to get back to you. I hope you are finally feeling better. By the way, this type of contact dermatitis from agave is apparently quite common. I was talking to a fellow who lives about three miles away and he was telling me that last year they had to clear away an agave and one of the men with him got a reaction from working with the plant. The worker's reaction was very much as you described: severe rash, malaise, and what I can only describe as a sense of depersonalization that lasted a couple of days.

    2. Oh thank you so much for replying to me. The malaise went first, gradually, and the swelling and rash have gone down but I'm left with an area of pink dry skin and few spots to remind me never to go near an agave again! It's thanks to your site that I was able to identify what was wrong with me and alleviate my concerns. Thanks.

    3. Sally, you are not alone. I know several people who have had this reaction. It will take a couple of months at least for the "pink dry skin" to completely go away. Glad to hear you are feeling better.

  2. I recently had a severe swelling of my tongue which resulted in an inability to swallow and a excessive production of saliva. I was hospitalised for a few days and was on a course of wide spectrum antibiotics and steroidal antihistamines. Doctors could not pin point the cause but after some consideration I recalled that I had pruned a large agave plant with an electric chain saw. I have come to the conclusion that this was the cause of my reaction. If you have any previous alergic reactions to plants I would strongly suggest staying away from this plant.