The new findings may support the theory that people with contact dermatitis and other allergies develop hyperactive immune systems that are primed to detect and stamp out tumors more quickly as they formed. Experts who analyzed allergy and cancer data from nearly 17,000 adults found men and women with contact allergies had “significantly lower” rates of breast and non-melanoma skin cancer compared with those without contact allergies. They said previous studies had shown allergies to substances such as pollen and dust mites could affect cancer rates. They thought people with common allergies like hay fever, asthma, metal allergies, poison ivy and others chemicals have a slight decreased risk of some cancers.
About 20 per cent of the population are allergic to one or more of the chemical and metals that constitute the baseline patch test panel. These irritants cause skin itching and inflammation. Skin allergies prompt the production of immune system T cells, which in turn can destroy cancer cells. Any protective effect may stem from the immune system going into “overdrive,” said Dr. Clifford W. Bassett, a New York City allergist and fellow of the American College of Allergy, Asthma and Immunology.
To read more go to: http://bmjopen.bmj.com/content/early/2011/06/15/bmjopen-2011-000084.short