For sensitive kids, it's look but don't touch.
Like many youngsters, 4-year-old Katie Young of Manchester, Wash., loved to play with furry caterpillars.She held them and petted them. And a week ago, she even cuddled one.
"It was black and yellow," she said. "I let it go in my bed."
She never found it, but Katie's love of the wiggly bug soon turned to hate after she woke up itching with tiny quills imbedded in her hand and arm.
Katie's mother, Julie Whalen, said her daughter's entire arm was pink, the inflammation centered on a dime-sized spot where the tiny quills poked out like black splinters.
Millions of children have played with caterpillars down through the ages. But only recently have scientists begun to focus on the biological agents that can cause severe allergic allergies in sensitive individuals, said Jennifer Boaz of the Washington Department of Agriculture.
Katie was lucky. A treatment with Benadryl was all she needed to relieve the itching and reduce the swelling in a couple of days. But, in extremely rare cases, patients have been known to go into anaphylactic shock - like the allergic reaction that certain people experience from being stung by a bee.
This spring turned out to be a good one for caterpillar lovers. The silver-spotted tiger moth - the black-and-yellow caterpillar that Katie had cuddled - is at a peak in its population cycle.
It's OK for kids to play with caterpillars, said Boaz, but they should be told not to pick them up with their bare hands.
"Pick them up on a stick or a leaf," she said. "Put them in a jar to look at them. But don't put them on your hands."
The spiny hairs on many fuzzy caterpillars contain a family of chemicals known as histamines. The chemicals are used as a defense against predators, such as birds.
Three people could handle the same caterpillar and come away with three different reactions, said Boaz. One person may suffer no reaction; one might feel a slight irritation and a third could experience a severe allergic rash or even breathing difficulty with a risk of death.
The silver-spotted tiger moth is a close relative of the gypsy moth, which has infested vast areas of the Eastern United States, said Boaz. During spring molting, the gypsy moth infestation can be so severe that caterpillar skins rain from the sky, and allergic people must be careful about breathing the al-ler-gens.
Wade Holbrook, an entomologist with the Washington Department of Agriculture who handles hundreds of insects, said he never touches any caterpillars he does not know.
While working in Florida, Holbrook said he touched a saddleback caterpillar and suffered a sudden, severe reaction.
"The saddleback is notorious for giving off spines," he said. "Just about anybody who picks up a saddleback will probably have a reaction."