Residents and visitors to north Norfolk are being warned to avoid brown-tail moth caterpillars nesting on the coast.
The caterpillars, which are orange, brown and hairy, have been found on the Norfolk Coastal Path national trail.
This is the second year the caterpillars have nested, causing Norfolk County Council to issue a warning to residents and tourists.
Norfolk County Council Norfolk Trails said on Twitter: "Do not disturb the tents and avoid the caterpillars, their hair is an irritant, which produces a lovely rash.
"Just see Trail Officer Ben's neck and don't ask him how it feels!"
The larvae are more commonly found on hawthorn and blackthorn bushes, as well as plums and cherry trees.
The caterpillars' hairs are an irritant which can break off as barbs, causing rashes, skin irritation, headaches and sometimes breathing difficulties.
A county council spokesman said: "This moth is a native species first recorded in Norfolk in 1834, primarily coastal areas.
"The caterpillars feed on a whole variety of trees and shrubs including brambles, oaks, hawthorns, cherries, and sea buckthorn. "
Last year, North Norfolk District Council advised people to avoid contact with the larvae that had began nesting on rails of the stairs leading to Cromer beach.
Cromer's much-loved goats were also at risk of the dangerous species of caterpillar that has triggered a public health warning.
The county council spokesman added: "The moth has a life cycle of about a year spends most of its life as a caterpillar, often as long as nine months.
"It usually only flies as an adult for less than a month.
"The hairs on the caterpillar can be an irritant and cause reactions in some people."
Brown-tail moth caterpillars are native to mainland Europe and are believed to have accidentally arrived in Britain in 2005 via Dutch trees imported from the continent.
They spend the winter months in webbing nests and emerge in the spring to feed.
The adults are active in July and August and lay batches of 150-250 eggs covered with brown hairs.
When fully grown the caterpillars can be up to 3cm in length.
If there is any accidental contact, members of the public should wash their hands in soapy water and clean their eyes with eyewash.
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