Although most aphids feed on plants, some instances of aphids biting or piercing human skin have been reported, according to SciLogs. The bites of these aphids can cause a rash.
One species known for attacking humans is the Ceratoglyphnia (Astero) styracicola, according to Entomological News. Anyone near an infected snowbell tree can be bitten. Another species that may bite is the Acyrthosiphon pisum or pea aphid. The A. pisum bites were documented during an inspection of a laboratory colony. The saliva of aphids contain toxic compounds that can cause irritation. Aphid bites cause red swelling for an hour followed by an itchy rash that can last up to three days.