The relevance of low skin temperature inhibiting histamine-induced itch to the location of contact urticarial symptoms in the fish processing industry.

Abstract

We have studied the influence of cold exposure on itch, erythema and wheal, in response to histamine scratch tests, in 14 volunteers. Cooling of the skin to less than 20 degrees C, by application of an ice cube for 30 min on the inside of the forearm, abolished itch and reduced erythema by approximately 50%, whereas the size of the wheal was unaffected by cooling. The observations bear significance for an explanation of the well-known observation that cold relieves itch. A normal itch response seems to require a continuous metabolic process in the skin, which is inhibited at temperatures less than 20 degrees C. The skin symptoms, itching and erythema, among workers in the fish processing industry are mainly localized to the forearms and backs of the hands, but only seldom to the fingers and palms, although they are in direct contact with fish products. Skin temperature measurements have shown that the temperature on the fingers and palms is less than 20 degrees C, while the temperature on the backs of the hands and forearms ranges from 25 to 30 degrees C. We therefore conclude that the skin temperature is an important factor for the location of skin symptoms among workers in the fish processing industry.