Caterpillar hair can be a cause of human health problems.
Picture from Jig Zone
Caterpillar hairs sometimes have venoms in them and can inflict serious human injuries ranging from urticarial dermatitis and atopic asthma to osteochondritis, renal failure, and intracerebral hemorrhage. Skin rashes are the most common, but there have been fatalities. Caterpillar hairs have also been known to cause kerato-conjunctivitis. The sharp barbs on the end of caterpillar hairs can get lodged in soft tissues and mucus membranes such as the eyes. Once they enter such tissues, they can be difficult to extract, often exacerbating the problem as they migrate across the membrane.