What's That Bug? does not endorse extermination

Subject: ugly, painful rash from a cocoon
Location: Nitro, WV
November 14, 2012 11:55 am
Two nights ago i tried on an old pair of pants that i kept in my basement closet. when i put them on i felt sting in my thigh that felt like a splinter and as i walked toward my mirror i felt a whole bunch of those stings so i ripped the pants off thinking there were bees in my pants or something. I immediately had a burning itchy rash all over my thigh. i looked in my pants to see if there were any bugs but all i noticed was group of small fibers that i thought maybe somehow my cat brought in stinging nettle hairs. Then this morning i noticed the cocoon in the floor where i tried the pants and realized that is what it was. I still have a rash 2 days later and its miserably itchy. I am curious to know what the cocoon is and how to make sure i get this insect far away from my house. Thank!
Signature: Lisa [Ed. Note:  Name withheld upon request]

Possibly Arctiid Cocoon

Dear Lisa,
Our first instinct is that this is the Cocoon of a Tiger Moth in the subfamily Arctiinae.  We didn’t search for an exact match, and though the color is wrong, this image from BugGuide shows the general form or cocoons in the subfamily.  We didn’t realize that Woolly Bears as the Arctiinae caterpillars are commonly called, had utricating hairs.  We have not noticed Woolly Bears in lists of stinging caterpillars we have linked to in the past.  The Ark in Space website is especially nice.  We wondered if perhaps this might be the cocoon of an Asp, but this image from BugGuidelooks very different.

Rash caused by Caterpillar Hairs

We will continue to research this matter to see if we can learn anything about the identity of the cocoon that gave you a rash.

Utricating Hairs


What's That Bug? does not endorse extermination
Location: West Virginia

12 Responses to Caterpillar Hairs produce human rash!!!

  1. Eric Burns says:

    I had exactly the same thing happen to me two days ago in the Snowy Mountains, Australia. The picture of the Arctiid Cacoon looks exactly like what fell out of my jacket sleeve.

  2. Satria Perdana says:

    I had this happen yesterday, I accidentally stepped on it inside my left shoe it was so itchy in all over my left foot and leg till now , the spines struck all over my foot i can’t remove it because its too deep.
    Please reply this comment and give any information to handle this, will my foot be okay if i don’t remove the spines? Will it be removed by the body by time? Thank you

  3. ROBERT DUPUIS says:

    I was cutting a nearly dead Popular tree down in my front yard in late Dec. (Quabbin Reservoir region of central MA) The days were warm but the night were below 32F. After dropping the tree I noticed rash on the inside of my wrist just above my palm (near all those veins you can see) Within an hour, my wrist swelled to the point of limited movement and the rash became very high in shape. It’s shape was that of a cocoon or a caterpillar body and there were a great deal (100 or so) small red prick marks surrounding the worm like rash all around it. I went inside and washed it and put some witch hazel on it and then slowly over 36 hours it mostly went away. Since then, I thought I had the flu,,,,recognizing my symptoms 3 weeks later are spot on to what I have read about the PERNICIOUS PUSS stings (not saying it was this insect yet the symptoms do match). headaches, nausea, vomiting, intense abdominal distress, lymphadenopathy, lymphadenitis. I’ve had all of this without a fever. I’m feeling better slowly yet there was a point that I could not even speak, I thought I had Laryngitis….horrible swelling of all of the glands in my neck, lasted about 4 days, started out a day or so after the bite and grew to extreme discomfort after 4 days….. NOt sure if there is any treatment this late in the game yet i’m heading to the doctor

    • Debra says:

      I had a cocoon in my shoe unbeknownst to me and I was barefoot. Within 4 hours of removing shoe the top of my foot was swollen , red to the shape of cocoon, so much pain and itch I could hardly stand it . After 2 doc appts they said I was having an illergic reaction to the venom. I was put on prednisone and a steriod cream. I been taking this treatment for 7 days. Symptoms are now just starting to ease up. Shoes are now in garbage.

  4. Brooke says:

    I had a similar cacoon fall out of a container I had long stored in the garage. It fell on my arm and stuck to it. When I brushed it off little tiny hairs stuck to my arm and a rash appeared within a half hour. 2 weeks later and though the rash has gone down a little it still itches like crazy! I live in NW PA with a large population of Wooly Bears.

  5. Meghab says:

    I just had one of these buggers stuck on my shoulder! Ah! I live in the southern tier of NY. My arm is all tingly. I’m a little freaked out. I used tweezers to pick out what I can but still some stuck in.

  6. Meredith says:

    I came into contact with this 5 days ago. It was on the back of a chair and I rested my back on it for about 10 minutes before I felt stinging/prickling! That night it was a bunch of tiny red dots. Now they are bigger red marks and are itchy! I went to the doc today and got some ointment for it. Hoping that helps the itching and reduces the swelling. Also hoping I don’t experience any more symptoms as time passes!

  7. Lynn says:

    I just came in contact with one of these cocoons; the cocoon was inside my oven mitt and when I put my hand inside the oven mitt I got hundreds of tiny splinters in two fingers. Those fingers are now swollen and very, very itchy! To those of you who have had this happen before, did you try Benadryl? I was planning to start there and hopefully get some relief.

  8. Luna says:

    There was a tornado so I went downstairs to sit on my couch. When I got up to pee, my leg was hurting bad so I went to look in the mirror. When I saw that there was a patch of redness, I felt it. It felt like small fibers stuck! I then take duct tape and rip the fibers out which gave me relief considering the fibers made it hurt when I walked. 2 days later , it’s exaclty like the picture of the rash shown above and I don’t know what to do. What helps people in the past that had this happen.

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