Contact dermatitis.
Ted is a 38 year old service technician for a large chemical company servicing cooling towers at a car manufacturing plant. While blending a batch of chemicals, he accidentally splashed cooling tower fluid, Kathon, an isothiazolin-3 derivative, over his left forearm. He was wearing long sleeved overalls and safety glasses at the time. About 15 minutes later, Ted experienced some itchiness of his forearm and proceeded to wash the area. He did not change his uniform. Five hours later he experienced severe pain of the forearm. Inspection revealed a 5 cm dermal burn with obvious blistering over the left forearm. He sought medical treatment and was treated conservatively with routine burn dressings. The skin blistering healed after seven days. Ted returned to work undertaking full duties. When undertaking mixing of cooling tower chemicals he developed an itchy rash of the forearms that appeared to be spreading to his hand and shoulder areas. This skin irritation occurred even when there was no contact with cooling tower fluids.