Urticating caterpillars give you hives. No, really.You may recognize the term “hives” as the red, itchy, stinging,swollen areas of skin that have tortured you or someone you know.The technical term for hives is urticaria. And a number of thingscan cause it.One cause you probably wouldn’t think of is a caterpillar.Urticating caterpillars are moth larvae that get their name fromthe fact that they sting people in a way that produces urticaria.These creepy crawlers have hollow spines that hold an irritatingfluid that causes stinging and burning in a person’s skin. InGeorgia, urticating caterpillars show up in the late summer andfall. The two most common in Georgia are the saddleback and pusscaterpillars.Saddleback caterpillarThe saddleback (Sibine stimulea) is the one most oftenencountered. The full-grown caterpillar is striking. It’s about 1inch long, and the middle of the body is green with a white orcream margin and a large, oval, dark brown spot in the center,also with a white margin. The white-bordered brown spot lookslike a saddle and blanket, giving it its name.Its startling color scheme doesn’t hide the fact that it bristleswith spines. It has pairs of dark brown, spiny “horns” on thefront and rear ends. And in-between are small clumps of spinesalong the lower margin of the green area.Saddlebacks are generally solitary feeders. However, early-stagelarvae may be somewhat gregarious. They show up in many trees,shrubs and other plants, including corn. But they’re most commonon oaks, elms, dogwoods and various fruit trees.Their sting produces an immediate burningsensation, followed by inflammation, swelling and a red rash.Puss caterpillarThe puss caterpillar (Megalopyge opercularis) looks alittle like something the cat might have coughed up. It’s hairy.Really hairy. It’s more than an inch long, with short, toxicspines hidden underneath its brown or gray fur. The hairs at therear end form a tail-like tuft, with the head tucked under thefront.Puss caterpillars feed on oaks, pecans, persimmon, fruit trees,roses and other trees and shrubs. They’re typically loners,although you may find several on a given tree.These little dusters only look like harmless hair balls. Theyactually cause the most painful and severe reaction of anyurticating species in the United States.When your skin brushes against the puss caterpillar, the spinesbreak off, releasing an irritating fluid that produces animmediate stinging, burning sensation. The numbness and swellingthat follow may extend to your whole arm or leg in severe cases.Red blotches may persist for a couple of days, accompanied by aweeping rash. Associated lymph nodes may swell and be tender for12 to 24 hours. Systemic reactions may include nausea andvomiting.What to doIf you’re gardening, mowing the lawn, picking fruit or working inother ways in which you might brush against urticatingcaterpillars, wear long pants, long-sleeve shirts and gloves.If one stings you, treat the symptoms. To remove any spines stillin the skin, gently stick a piece of adhesive tape to the siteand then pull it away. Applying cold compresses can lessen thepain and swelling.Over-the-counter pain medications and topical hydrocortisonecreams may help. If the symptoms include systemic reactions ordon’t begin to ease up a couple of days, contact a physician.