Can colour on the skin produce symptoms in other parts of the body?

Yes.  One twelve month old child described as “failure to thrive” attended for diet investigation. The family were very pleased when he started gaining weight and stopped looking fragile on the diet. Mum took his to a playgroup and made sure no one gave him any food. The children played with coloured water and he came home with his hands yellow. She rang me the next day saying he had diarrhoea but was not looking sick. I checked that he did not have an increased temperature and suggested she wait a couple of days watching to see if it got worse or the child got distressed in any other way. When it had not improved over five days she saw the doctor and he discussed the tests they would begin to investigate it. On day seven the diarrhoea disappeared as abruptly as it had appeared and did not return. I had had many reports of hyperactive children reacting to dye through the skin, affecting attention, activity and sleep, but that was a first for such a clear gut reaction.