An environmental investigation is under way after three children who went canoeing off the coast at Worthing broke out in an itchy red rash.

Seawater samples are being tested to discover the cause of the problem and other sufferers are being urged to come forward.

The rash appeared after the group of friends set off from near Wallace Avenue on Saturday afternoon.

Diana Connor, whose 12-year-old son Daniel was among those affected, said it took 24 hours to subside.

She said: "It was a very fine red rash on his chest and legs. He said it itched when he moved and put on his T-shirt."

The youngsters had been in the water just over an hour when they noticed the rashes.

Mrs Connor, of Ripley Road, said: "The only link we could think of was that all three had been in the sea.

"My son hasn't said he saw any jellyfish around so I don't know if it was caused by the seawater or seaweed. It has made me very wary about letting him back in the sea."

She said the three went home to take cold showers and antihistamine tablets but did not need to seek medical treatment.

Today the Environment Agency said it was investigating. A spokeswoman said they had not yet received the results of seawater samples.

She said: "We don't know of any other problems and we haven't had any reports of pollution so this may be a one-off incident.

"We do regular tests throughout the summer months and at the moment we regard the bathing water quality as very good."

Keith Chamberlain, environmental health manager at Worthing Borough Council, appealed for anyone else who came out in a rash to get in contact.

He said: "It is a mystery. It could be any number of things such as the spores from jellyfish or an allergic reaction to the seaweed."

Worthing beach this year lost the right to fly the coveted Seaside Award flag for the first time in seven years.

The water quality did not meet strict criteria set by environment charity Encams, which is behind the Keep Britain Tidy campaign.

Although it failed on water quality, the beach received "excellent" ratings in 15 categories - just one short of the number needed to win a Blue Flag.